7.E: El enlace químico y la geometría molecular (Ejercicios)
7.1: Enlace iónico
Q7.1.1
¿Un catión gana protones para formar una carga positiva o pierde electrones?
S7.1.1
Los protones del núcleo no cambian durante las reacciones químicas normales. Solo se mueven los electrones externos. Cargas positivas
se forman cuando se pierden electrones.
Q7.1.2
El sulfato de hierro (III) [Fe 2 (SO 4 ) 3 ] está compuesto de Fe 3+ y \(\ce{SO4^2-}\ iones. Explique por qué no se carga una muestra de sulfato de hierro (III)
Q7.1.3
¿Cuál de los siguientes átomos se esperaría que forme iones negativos en compuestos iónicos binarios y cuál sería se espera que formen iones positivos: P, I, Mg, Cl, In, Cs, O, Pb, Co?
S7.1.3
P, I, Cl y O formarían aniones porque no son metales. Mg, In, Cs, Pb y Co formarían cationes porque son rieles
Q7.1.4
Which of the following atoms would be expected to form negative ions in binary ionic compounds and which would be expected to form positive ions: Br, Ca, Na, N, F, Al, Sn, S, Cd?
Q7.1.5
Predecir la carga de los iones monoatómicos formados a partir de los siguientes átomos en compuestos iónicos binarios:
A. P
B. Mg
C. Al
D. O
E. Cl
F. C
S7.1.5
P 3– ; Mg 2+ ; Al 3+ ; O 2– ; Cl – ; Cs +
Q7.1.6
Predecir la carga de los iones monoatómicos formados a partir de los siguientes átomos en compuestos iónicos binarios
- Sr
- K
- N
- S
- In
S7.1.6
- I -
- Sr 2+
- K +
- N 3-
- S 2-
- In 3+
Q7.1.7
Escriba la configuración electrónica para cada uno de los siguientes iones:
- As 3–
- I –
- Be 2+
- Cd 2+
- O 2–
- Ga 3+
- Li +
- (h) N 3–
- (i) Sn 2+
- (j) Co 2+
- (k) Fe 2+
- (l) As 3+
S7.1.7
[Ar]4 s 2 3 d 10 4 p 6 ; [Kr]4 d 10 5 s 2 5 p 6 1 s 2 [Kr]4 d 10 ; [He]2 s 2 2 p 6 ; [Ar]3 d 10 ; 1 s 2 (h) [He]2 s 2 2 p 6 (i) [Kr]4 d 10 5 s 2 (j) [Ar]3 d 7 (k) [Ar]3 d 6 , (l) [Ar]3 d 10 4 s 2
Q7.1.8
Escriba la configuración electrónica de los iones monoatómicos formados a partir de los siguientes elementos (que forman la mayor concentración de iones monoatómicos en agua de mar):
- Cl
- Na
- Mg
- Ca
- K
- Br
- Sr
- (h) F
Q7.1.9
Escriba la configuración electrónica completa para cada uno de los siguientes átomos y para el ion monoatómico que se encuentra en binario iónico compuestos que contienen el elemento
- Al
- Br
- Sr
- Li
- As
- S
S7.1.9
1 s 2 2 s 2 2 p 6 3 s 2 3 p 1 ; Al 3+ : 1 s 2 2 s 2 2 p 6 ; 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 3 d 10 4 s 2 4 p 5 ; 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 3 d 10 4 s 2 4 p 6 ; 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 3 d 10 4 s 2 4 p 6 5 s 2 ;
Sr 2+ : 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 3 d 10 4 s 2 4 p 6 ; 1 s 2 2 s 1 ;
Li + : 1 s 2 ; 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 3 d 10 4 s 2 4 p 3 ; 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 3 d 10 4 s 2 4 p 6 ; 1 s 2 2 s 2 2 p 6 3 s 2 3 p 4 ; 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6
Q7.1.10
A partir de las etiquetas de varios productos comerciales, prepare una lista de seis compuestos iónicos en los productos. Para cada compuesto, escribe la fórmula. (Es posible que deba buscar algunas fórmulas en una referencia adecuada).
7.3: Covalent Bonding
¿Por qué es incorrecto hablar de una molécula de NaCl sólido?
El NaCl consiste en iones discretos dispuestos en una red cristalina, no moléculas unidas covalentemente.
¿Qué información puede utilizar para predecir si un enlace entre dos átomos es covalente o iónico?
Predecir cuáles de los siguientes compuestos son iónicos y cuáles son covalentes, según la ubicación de sus átomos constituyentes en la tabla periodica
- Cl 2 CO
- MnO
- NCl 3
- CoBr 2
- K 2 S
- CO
- CaF 2
- (h) HI
- (i) CaO
- (j) IBr
- (k) CO 2
iónico:: (b), (d), (e), (g), y (i); covalente : (a), (c), (f), (h), (j), and (k)
Explique la diferencia entre un enlace covalente no polar, un enlace covalente polar y un enlace iónico.
A partir de su posición en la tabla periódica, determine qué átomo de cada par es más electronegativo:
- Br o Cl
- N o O
- S o O
- P o S
- Si o N
- Ba o P
- N o K
Cl; O; O; S; N; P; N
A partir de su posición en la tabla periódica, determine qué átomo de cada par es más electronegativo:
- N or P
- N or Ge
- S or F
- Cl or S
- H or C
- Se or P
- C or Si
Desde sus posiciones en la tabla periódica, organice los átomos en cada una de las siguientes series en orden creciente electronegatividad:
- C, F, H, N, O
- Br, Cl, F, H, I
- F, H, O, P, S
- Al, H, Na, O, P
- Ba, H, N, O, As
H, C, N, O, F; H, I, Br, Cl, F; H, P, S, O, F; Na, Al, H, P, O; Ba, H, As, N, O
Desde sus posiciones en la tabla periódica, organice los átomos en cada una de las siguientes series en orden creciente electronegatividad:
- As, H, N, P, Sb
- Cl, H, P, S, Si
- Br, Cl, Ge, H, Sr
- Ca, H, K, N, Si
- Cl, Cs, Ge, H, Sr
¿Qué átomos pueden unirse al azufre para producir una carga parcial positiva en el átomo de azufre?
N, O, F, and Cl
¿Cuál es el enlace más polar?
- C–C
- C–H
- N–H
- O–H
- Se–H
Identifique el enlace más polar en cada uno de los siguientes pares de enlaces:
- HF or HCl
- NO or CO
- SH or OH
- PCl or SCl
- CH or NH
- SO or PO
- CN or NN
HF; CO; OH; PCl; NH; PO; CN
¿Cuáles de las siguientes moléculas o iones contienen enlaces polares?
- O 3
- S 8
- \(\ce{O2^2-}\)
- \(\ce{NO3-}\)
- CO 2
- H 2 S
- \(\ce{BH4-}\)
7.4: Símbolos y estructuras de Lewis
Q7.4.1
Escriba los símbolos de Lewis para cada uno de los siguientes iones
- As 3–
- I –
- Be 2+
- O 2–
- Ga 3+
- Li +
- N 3–
S7.4.1
ocho electrones:
ocho electrones:
sin electrones Be 2+ ;
ocho electrones:
sin electrones Ga 3+ ;
sin electrones Li + ;
ocho electrones:
Q7.4.2
Muchos iones monoatómicos se encuentran en el agua de mar, incluidos los iones formados a partir de la siguiente lista de elementos. Escribe el Lewis símbolos para los iones monoatómicos formados a partir de los siguientes elementos:
- Cl
- Na
- Mg
- Ca
- K
- Br
- Sr
- F
Q7.4.3
Escriba los símbolos de Lewis de los iones en cada uno de los siguientes compuestos iónicos y los símbolos de Lewis del átomo del cual se forman:
- MgS
- Al 2 O 3
- GaCl 3
- K 2 O
- Li 3 N
- KF
(a)
;
(b)
;
(c)
;
(d)
;
(e)
;
(f)
En las estructuras de Lewis enumeradas aquí, M y X representan varios elementos en el tercer período de la tabla periódica. Escribe el fórmula de cada compuesto usando los símbolos químicos de cada elemento:
(a)
(b)
(c)
(d)
Escriba la estructura de Lewis para la molécula diatómica P, una forma inestable de fósforo que se encuentra en el fósforo de alta temperatura vapor
Escriba estructuras de Lewis para lo siguiente:
- H 2
- HBr
- PCl 3
- SF 2
- H 2 CCH 2
- HNNH
- H 2 CNH
- (h) NO –
- (i) N 2
- (j) CO
- (k) CN –
Escriba estructuras de Lewis para lo siguiente:
- O 2
- H 2 CO
- AsF 3
- ClNO
- SiCl 4
- H 3 O +
- \(\ce{NH4+}\)
- (h) \(\ce{BF4-}\)
- (i) HCCH
- (j) ClCN
- (k) \(\ce{C2^2+}\)
(a)
En este caso, la estructura de Lewis es inadecuada para representar el hecho de que los estudios experimentales han mostrado dos electrones desapareados en cada molécula de oxígeno
(b)
;
(c)
;
(d)
;
(e)
;
(f)
;
(g)
;
(h)
;
(i)
;
(j)
;
(k)
Escriba estructuras de Lewis para lo siguiente:
- ClF 3
- PCl 5
- BF 3
- \(\ce{PF6-}\)
Escriba estructuras de Lewis para lo siguiente:
- SeF 6
- XeF 4
- \(\ce{SeCl3+}\)
- Cl 2 BBCl 2 (contiene un enlace B–B )
SeF 6 :
;
XeF 4 :
;
\(\ce{SeCl3+}\):
;
Cl 2 BBCl 2 :
Escriba estructuras de Lewis para lo siguiente:
- \(\ce{PO4^3-}\)
- \(\ce{ICl4-}\)
- \(\ce{SO3^2-}\)
- HONO
Corrija la siguiente afirmación: “Los enlaces en el PbCl 2 sólido son iónicos; el enlace en una molécula de HCl es covalente. Por lo tanto, todos los electrones de valencia en PbCl 2 se encuentran en los iones Cl – , y todos los electrones de valencia en una molécula de HCl se comparten entre los átomos de H y Cl ".
Se transfieren dos electrones de valencia por átomo de Pb a los átomos de Cl; el ion Pb 2+ resultante tiene una configuración de capa de valencia de 6 s 2 . Dos de los electrones de valencia en la molécula de HCl se comparten, y los otros seis están ubicados en el átomo de Cl como pares solitarios de electrones.
Escriba estructuras de Lewis para las siguientes moléculas o iones
- SbH 3
- XeF 2
- Se 8 (una molécula cíclica con un anillo de ocho átomos de Se)
El metanol, H 3 COH , se usa como combustible en algunos autos de carrera. El etanol, H 3 COH , se utiliza ampliamente como combustible de motor en Brasil. Ambas cosas el metanol y el etanol producen CO 2 y H 2 O cuando se queman. Escribe las ecuaciones químicas para estas reacciones de combustión. utilizando estructuras de Lewis en lugar de fórmulas químicas
Many planets in our solar system contain organic chemicals including methane (CH 4 ) and traces of ethylene (C 2 H 4 ), ethane (C 2 H 6 ), propyne (H 3 CCCH), and diacetylene (HCCCCH). Write the Lewis structures for each of these molecules.
Carbon tetrachloride was formerly used in fire extinguishers for electrical fires. It is no longer used for this purpose because of the formation of the toxic gas phosgene, Cl 2 CO. Write the Lewis structures for carbon tetrachloride and phosgene.
Identify the atoms that correspond to each of the following electron configurations. Then, write the Lewis symbol for the common ion formed from each atom:
- 1 s 2 2 s 2 2 p 5
- 1 s 2 2 s 2 2 p 6 3 s 2
- 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 10
- 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 10 4 p 4
- 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 10 4 p 1
The arrangement of atoms in several biologically important molecules is given here. Complete the Lewis structures of these molecules by adding multiple bonds and lone pairs. Do not add any more atoms.
the amino acid serine:
urea:
pyruvic acid:
uracil:
carbonic acid:
(a)
;
(b)
;
(c)
;
(d)
;
(e)
A compound with a molar mass of about 28 g/mol contains 85.7% carbon and 14.3% hydrogen by mass. Write the Lewis structure for a molecule of the compound.
A compound with a molar mass of about 42 g/mol contains 85.7% carbon and 14.3% hydrogen by mass. Write the Lewis structure for a molecule of the compound.
Two arrangements of atoms are possible for a compound with a molar mass of about 45 g/mol that contains 52.2% C, 13.1% H, and 34.7% O by mass. Write the Lewis structures for the two molecules.
How are single, double, and triple bonds similar? How do they differ?
Each bond includes a sharing of electrons between atoms. Two electrons are shared in a single bond; four electrons are shared in a double bond; and six electrons are shared in a triple bond.
7.5: Formal Charges and Resonance
Write resonance forms that describe the distribution of electrons in each of these molecules or ions.
- selenium dioxide, OSeO
- nitrate ion, \(\ce{NO3-}\)
- nitric acid, HNO 3 (N is bonded to an OH group and two O atoms)
- benzene, C 6 H 6 :
the formate ion:
Write resonance forms that describe the distribution of electrons in each of these molecules or ions.
- sulfur dioxide, SO 2
- carbonate ion, \(\ce{CO3^2-}\)
- hydrogen carbonate ion, \(\ce{HCO3-}\) (C is bonded to an OH group and two O atoms)
- pyridine:
the allyl ion:
(a)
;
(b)
;
(c)
;
(d)
;
(e)
Write the resonance forms of ozone, O 3 , the component of the upper atmosphere that protects the Earth from ultraviolet radiation.
Sodium nitrite, which has been used to preserve bacon and other meats, is an ionic compound. Write the resonance forms of the nitrite ion, \(\ce{NO2-}\).
In terms of the bonds present, explain why acetic acid, CH 3 CO 2 H, contains two distinct types of carbon-oxygen bonds, whereas the acetate ion, formed by loss of a hydrogen ion from acetic acid, only contains one type of carbon-oxygen bond. The skeleton structures of these species are shown:
Write the Lewis structures for the following, and include resonance structures where appropriate. Indicate which has the strongest carbon-oxygen bond.
- CO 2
- CO
(a)
(b)
CO has the strongest carbon-oxygen bond because there is a triple bond joining C and O. CO 2 has double bonds.
Toothpastes containing sodium hydrogen carbonate (sodium bicarbonate) and hydrogen peroxide are widely used. Write Lewis structures for the hydrogen carbonate ion and hydrogen peroxide molecule, with resonance forms where appropriate.
Determine the formal charge of each element in the following:
- HCl
- CF 4
- PCl 3
- PF 5
H: 0, Cl: 0; C: 0, F: 0; P: 0, Cl 0; P: 0, F: 0
Determine the formal charge of each element in the following:
- H 3 O +
- \(\ce{SO4^2-}\)
- NH 3
- \(\ce{O2^2-}\)
- H 2 O 2
Calculate the formal charge of chlorine in the molecules Cl 2 , BeCl 2 , and ClF 5 .
Cl in Cl 2 : 0; Cl in BeCl 2 : 0; Cl in ClF 5 : 0
Calculate the formal charge of each element in the following compounds and ions:
- F 2 CO
- NO –
- \(\ce{BF4-}\)
- \(\ce{SnCl3-}\)
- H 2 CCH 2
- ClF 3
- SeF 6
- (h) \(\ce{PO4^3-}\)
Draw all possible resonance structures for each of these compounds. Determine the formal charge on each atom in each of the resonance structures:
- O 3
- SO 2
- \(\ce{NO2-}\)
- \(\ce{NO3-}\)
;
(b)
;
(c)
;
(d)
Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in nitrosyl chloride: ClNO or ClON?
Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in hypochlorous acid: HOCl or OClH?
HOCl
Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in sulfur dioxide: OSO or SOO?
Draw the structure of hydroxylamine, H 3 NO, and assign formal charges; look up the structure. Is the actual structure consistent with the formal charges?
The structure that gives zero formal charges is consistent with the actual structure:
Iodine forms a series of fluorides (listed here). Write Lewis structures for each of the four compounds and determine the formal charge of the iodine atom in each molecule:
- IF
- IF 3
- IF 5
- IF 7
Write the Lewis structure and chemical formula of the compound with a molar mass of about 70 g/mol that contains 19.7% nitrogen and 80.3% fluorine by mass, and determine the formal charge of the atoms in this compound.
NF 3 ;
Which of the following structures would we expect for nitrous acid? Determine the formal charges:
Sulfuric acid is the industrial chemical produced in greatest quantity worldwide. About 90 billion pounds are produced each year in the United States alone. Write the Lewis structure for sulfuric acid, H 2 SO 4 , which has two oxygen atoms and two OH groups bonded to the sulfur.
7.6: Strengths of Ionic and Covalent Bonds
Which bond in each of the following pairs of bonds is the strongest?
- C–C or \(\mathrm{C=C}\)
- C–N or \(\mathrm{C≡N}\)
- \(\mathrm{C≡O}\) or \(\mathrm{C=O}\)
- H–F or H–Cl
- C–H or O–H
- C–N or C–O
Using the bond energies in Table , determine the approximate enthalpy change for each of the following reactions:
- \(\ce{H2}(g)+\ce{Br2}(g)⟶\ce{2HBr}(g)\)
- \(\ce{CH4}(g)+\ce{I2}(g)⟶\ce{CH3I}(g)+\ce{HI}(g)\)
- (c) \(\ce{C2H4}(g)+\ce{3O2}(g)⟶\ce{2CO2}(g)+\ce{2H2O}(g)\)
- −114 kJ;
- 30 kJ;
- (c) −1055 kJ
Using the bond energies in Table , determine the approximate enthalpy change for each of the following reactions:
- \(\ce{Cl2}(g)+\ce{3F2}(g)⟶\ce{2ClF3}(g)\)
- \(\mathrm{H_2C=CH_2}(g)+\ce{H2}(g)⟶\ce{H3CCH3}(g)\)
- (c) \(\ce{2C2H6}(g)+\ce{7O2}(g)⟶\ce{4CO2}(g)+\ce{6H2O}(g)\)
When a molecule can form two different structures, the structure with the stronger bonds is usually the more stable form. Use bond energies to predict the correct structure of the hydroxylamine molecule:
The greater bond energy is in the figure on the left. It is the more stable form.
How does the bond energy of HCldiffer from the standard enthalpy of formation of HCl( g )?
Using the standard enthalpy of formation data in Appendix G , show how the standard enthalpy of formation of HCl( g ) can be used to determine the bond energy.
\(\ce{HCl}(g)⟶\dfrac{1}{2}\ce{H2}(g)+\dfrac{1}{2}\ce{Cl2}(g)\hspace{20px}ΔH^\circ_1=−ΔH^\circ_{\ce f[\ce{HCl}(g)]}\\
\dfrac{1}{2}\ce{H2}(g)⟶\ce{H}(g)\hspace{105px}ΔH^\circ_2=ΔH^\circ_{\ce f[\ce H(g)]}\\
\underline{\dfrac{1}{2}\ce{Cl2}(g)⟶\ce{Cl}(g)\hspace{99px}ΔH^\circ_3=ΔH^\circ_{\ce f[\ce{Cl}(g)]}}\\
\ce{HCl}(g)⟶\ce{H}(g)+\ce{Cl}(g)\hspace{58px}ΔH^\circ_{298}=ΔH^\circ_1+ΔH^\circ_2+ΔH^\circ_3\)
\(\begin{align}
D_\ce{HCl}=ΔH^\circ_{298}&=ΔH^\circ_{\ce f[\ce{HCl}(g)]}+ΔH^\circ_{\ce f[\ce H(g)]}+ΔH^\circ_{\ce f[\ce{Cl}(g)]}\\
&=\mathrm{−(−92.307\:kJ)+217.97\:kJ+121.3\:kJ}\\
&=\mathrm{431.6\:kJ}
\end{align}\)
Using the standard enthalpy of formation data in Appendix G , calculate the bond energy of the carbon-sulfur double bond in CS 2 .
Using the standard enthalpy of formation data in Appendix G , determine which bond is stronger: the S–F bond in SF 4 ( g ) or in SF 6 ( g )?
The S–F bond in SF 4 is stronger.
Using the standard enthalpy of formation data in Appendix G , determine which bond is stronger: the P–Cl bond in PCl 3 ( g ) or in PCl 5 ( g )?
Complete the following Lewis structure by adding bonds (not atoms), and then indicate the longest bond:
The C–C single bonds are longest.
Use the bond energy to calculate an approximate value of Δ H for the following reaction. Which is the more stable form of FNO 2 ?
Use principles of atomic structure to answer each of the following: 1
- The radius of the Ca atom is 197 pm; the radius of the Ca 2+ ion is 99 pm. Account for the difference.
- The lattice energy of CaO( s ) is –3460 kJ/mol; the lattice energy of K 2 O is –2240 kJ/mol. Account for the difference.
- (c) Given these ionization values, explain the difference between Ca and K with regard to their first and second ionization energies.
| Element | First Ionization Energy (kJ/mol) | Second Ionization Energy (kJ/mol) |
|---|---|---|
| K | 419 | 3050 |
| Ca | 590 | 1140 |
The first ionization energy of Mg is 738 kJ/mol and that of Al is 578 kJ/mol. Account for this difference.
When two electrons are removed from the valence shell, the Ca radius loses the outermost energy level and reverts to the lower n = 3 level, which is much smaller in radius. The +2 charge on calcium pulls the oxygen much closer compared with K, thereby increasing the lattice energy relative to a less charged ion. (c) Removal of the 4 s electron in Ca requires more energy than removal of the 4 s electron in K because of the stronger attraction of the nucleus and the extra energy required to break the pairing of the electrons. The second ionization energy for K requires that an electron be removed from a lower energy level, where the attraction is much stronger from the nucleus for the electron. In addition, energy is required to unpair two electrons in a full orbital. For Ca, the second ionization potential requires removing only a lone electron in the exposed outer energy level. In Al, the removed electron is relatively unprotected and unpaired in a p orbital. The higher energy for Mg mainly reflects the unpairing of the 2 s electron.
The lattice energy of LiF is 1023 kJ/mol, and the Li–F distance is 200.8 pm. NaF crystallizes in the same structure as LiF but with a Na–F distance of 231 pm. Which of the following values most closely approximates the lattice energy of NaF: 510, 890, 1023, 1175, or 4090 kJ/mol? Explain your choice.
For which of the following substances is the least energy required to convert one mole of the solid into separate ions?
- MgO
- SrO
- (c) KF
- CsF
- MgF 2
(d)
The reaction of a metal, M, with a halogen, X 2 , proceeds by an exothermic reaction as indicated by this equation: \(\ce{M}(s)+\ce{X2}(g)⟶\ce{MX2}(s)\). For each of the following, indicate which option will make the reaction more exothermic. Explain your answers.
- a large radius vs. a small radius for M +2
- a high ionization energy vs. a low ionization energy for M
- (c) an increasing bond energy for the halogen
- a decreasing electron affinity for the halogen
- an increasing size of the anion formed by the halogen
The lattice energy of LiF is 1023 kJ/mol, and the Li–F distance is 201 pm. MgO crystallizes in the same structure as LiF but with a Mg–O distance of 205 pm. Which of the following values most closely approximates the lattice energy of MgO: 256 kJ/mol, 512 kJ/mol, 1023 kJ/mol, 2046 kJ/mol, or 4008 kJ/mol? Explain your choice.
4008 kJ/mol; both ions in MgO have twice the charge of the ions in LiF; the bond length is very similar and both have the same structure; a quadrupling of the energy is expected based on the equation for lattice energy
Which compound in each of the following pairs has the larger lattice energy? Note: Mg 2+ and Li + have similar radii; O 2– and F – have similar radii. Explain your choices.
- MgO or MgSe
- LiF or MgO
- (c) Li 2 O or LiCl
- Li 2 Se or MgO
Which compound in each of the following pairs has the larger lattice energy? Note: Ba 2+ and
K + have similar radii; S 2– and Cl – have similar radii. Explain your choices.
- K 2 O or Na 2 O
- K 2 S or BaS
- (c) KCl or BaS
- BaS or BaCl 2
Na 2 O; Na + has a smaller radius than K + ; BaS; Ba has a larger charge than K; (c) BaS; Ba and S have larger charges; BaS; S has a larger charge
Which of the following compounds requires the most energy to convert one mole of the solid into separate ions?
- MgO
- SrO
- (c) KF
- CsF
- MgF 2
Which of the following compounds requires the most energy to convert one mole of the solid into separate ions?
- K 2 S
- K 2 O
- (c) CaS
- Cs 2 S
- CaO
(e)
The lattice energy of KF is 794 kJ/mol, and the interionic distance is 269 pm. The Na–F
distance in NaF, which has the same structure as KF, is 231 pm. Which of the following values is the closest approximation of the lattice energy of NaF: 682 kJ/mol, 794 kJ/mol, 924 kJ/mol, 1588 kJ/mol, or 3175 kJ/mol? Explain your answer.
7.7: Molecular Structure and Polarity
Explain why the HOH molecule is bent, whereas the HBeH molecule is linear.
The placement of the two sets of unpaired electrons in water forces the bonds to assume a tetrahedral arrangement, and the resulting HOH molecule is bent. The HBeH molecule (in which Be has only two electrons to bond with the two electrons from the hydrogens) must have the electron pairs as far from one another as possible and is therefore linear.
What feature of a Lewis structure can be used to tell if a molecule’s (or ion’s) electron-pair geometry and molecular structure will be identical?
Explain the difference between electron-pair geometry and molecular structure.
Space must be provided for each pair of electrons whether they are in a bond or are present as lone pairs. Electron-pair geometry considers the placement of all electrons. Molecular structure considers only the bonding-pair geometry.
Why is the H–N–H angle in NH 3 smaller than the H–C–H bond angle in CH 4 ? Why is the H–N–H angle in \(\ce{NH4+}\) identical to the H–C–H bond angle in CH 4 ?
Explain how a molecule that contains polar bonds can be nonpolar.
As long as the polar bonds are compensated (for example. two identical atoms are found directly across the central atom from one another), the molecule can be nonpolar.
As a general rule, MX n molecules (where M represents a central atom and X represents terminal atoms; n = 2 – 5) are polar if there is one or more lone pairs of electrons on M. NH 3 (M = N, X = H, n = 3) is an example. There are two molecular structures with lone pairs that are exceptions to this rule. What are they?
Predict the electron pair geometry and the molecular structure of each of the following molecules or ions:
- SF 6
- PCl 5
- (c) BeH 2
- \(\ce{CH3+}\)
- Both the electron geometry and the molecular structure are octahedral.
- Both the electron geometry and the molecular structure are trigonal bipyramid.
- (c) Both the electron geometry and the molecular structure are linear.
- Both the electron geometry and the molecular structure are trigonal planar.
Identify the electron pair geometry and the molecular structure of each of the following molecules or ions:
- \(\ce{IF6+}\)
- CF 4
- (c) BF 3
- \(\ce{SiF5-}\)
- BeCl 2
What are the electron-pair geometry and the molecular structure of each of the following molecules or ions?
- ClF 5
- \(\ce{ClO2-}\)
- (c) \(\ce{TeCl4^2-}\)
- PCl 3
- SeF 4
- \(\ce{PH2-}\)
electron-pair geometry: octahedral, molecular structure: square pyramidal; electron-pair geometry: tetrahedral, molecular structure: bent; (c) electron-pair geometry: octahedral, molecular structure: square planar; electron-pair geometry: tetrahedral, molecular structure: trigonal pyramidal; electron-pair geometry: trigonal bypyramidal, molecular structure: seesaw; electron-pair geometry: tetrahedral, molecular structure: bent (109°)
Predict the electron pair geometry and the molecular structure of each of the following ions:
- H 3 O +
- \(\ce{PCl4-}\)
- (c) \(\ce{SnCl3-}\)
- \(\ce{BrCl4-}\)
- ICl 3
- XeF 4
- (g) SF 2
Identify the electron pair geometry and the molecular structure of each of the following molecules:
- ClNO (N is the central atom)
- CS 2
- (c) Cl 2 CO (C is the central atom)
- Cl 2 SO (S is the central atom)
- SO 2 F 2 (S is the central atom)
- XeO 2 F 2 (Xe is the central atom)
- (g) \(\ce{ClOF2+}\) (Cl is the central atom)
electron-pair geometry: trigonal planar, molecular structure: bent (120°); electron-pair geometry: linear, molecular structure: linear; (c) electron-pair geometry: trigonal planar, molecular structure: trigonal planar; electron-pair geometry: tetrahedral, molecular structure: trigonal pyramidal; electron-pair geometry: tetrahedral, molecular structure: tetrahedral; electron-pair geometry: trigonal bipyramidal, molecular structure: seesaw; (g) electron-pair geometry: tetrahedral, molecular structure: trigonal pyramidal
Predict the electron pair geometry and the molecular structure of each of the following:
- IOF 5 (I is the central atom)
- POCl 3 (P is the central atom)
- (c) Cl 2 SeO (Se is the central atom)
- ClSO + (S is the central atom)
- F 2 SO (S is the central atom)
- \(\ce{NO2-}\)
- (g) \(\ce{SiO4^4-}\)
Which of the following molecules and ions contain polar bonds? Which of these molecules and ions have dipole moments?
- ClF 5
- \(\ce{ClO2-}\)
- (c) \(\ce{TeCl4^2-}\)
- PCl 3
- SeF 4
- \(\ce{PH2-}\)
- (g) XeF 2
All of these molecules and ions contain polar bonds. Only ClF 5 , \(\ce{ClO2-}\), PCl 3 , SeF 4 , and \(\ce{PH2-}\) have dipole moments.
Which of the molecules and ions in Exercise contain polar bonds? Which of these molecules and ions have dipole moments?
- H 3 O +
- \(\ce{PCl4-}\)
- (c) \(\ce{SnCl3-}\)
- \(\ce{BrCl4-}\)
- ICl 3
- XeF 4
- (g) SF 2
Which of the following molecules have dipole moments?
- CS 2
- SeS 2
- (c) CCl 2 F 2
- PCl 3 (P is the central atom)
- ClNO (N is the central atom)
SeS 2 , CCl 2 F 2 , PCl 3 , and ClNO all have dipole moments.
Identify the molecules with a dipole moment:
- SF 4
- CF 4
- (c) Cl 2 CCBr 2
- CH 3 Cl
- H 2 CO
The molecule XF 3 has a dipole moment. Is X boron or phosphorus?
P
The molecule XCl 2 has a dipole moment. Is X beryllium or sulfur?
Is the Cl 2 BBCl 2 molecule polar or nonpolar?
nonpolar
There are three possible structures for PCl 2 F 3 with phosphorus as the central atom. Draw them and discuss how measurements of dipole moments could help distinguish among them.
Describe the molecular structure around the indicated atom or atoms:
- the sulfur atom in sulfuric acid, H 2 SO 4 [(HO) 2 SO 2 ]
- the chlorine atom in chloric acid, HClO 3 [HOClO 2 ]
- (c) the oxygen atom in hydrogen peroxide, HOOH
- the nitrogen atom in nitric acid, HNO 3 [HONO 2 ]
- the oxygen atom in the OH group in nitric acid, HNO 3 [HONO 2 ]
- the central oxygen atom in the ozone molecule, O 3
- (g) each of the carbon atoms in propyne, CH 3 CCH
- (h) the carbon atom in Freon, CCl 2 F 2
- (i) each of the carbon atoms in allene, H 2 CCCH 2
tetrahedral; trigonal pyramidal; (c) bent (109°); trigonal planar; bent (109°); bent (109°); (g) CH 3 CCH tetrahedral, CH 3 CCH linear; (h) tetrahedral; (i) H 2 CCCH 2 linear; H 2 CCCH 2 trigonal planar
Draw the Lewis structures and predict the shape of each compound or ion:
- CO 2
- \(\ce{NO2-}\)
- (c) SO 3
- \(\ce{SO3^2-}\)
A molecule with the formula AB 2 , in which A and B represent different atoms, could have one of three different shapes. Sketch and name the three different shapes that this molecule might have. Give an example of a molecule or ion for each shape.
A molecule with the formula AB 3 , in which A and B represent different atoms, could have one of three different shapes. Sketch and name the three different shapes that this molecule might have. Give an example of a molecule or ion that has each shape.
Draw the Lewis electron dot structures for these molecules, including resonance structures where appropriate:
- \(\ce{CS3^2-}\)
- CS 2
- (c) CS
predict the molecular shapes for \(\ce{CS3^2-}\) and CS 2 and explain how you arrived at your predictions
(a)
;
(b)
;
(c)
;
\(\ce{CS3^2-}\) includes three regions of electron density (all are bonds with no lone pairs); the shape is trigonal planar; CS 2 has only two regions of electron density (all bonds with no lone pairs); the shape is linear
What is the molecular structure of the stable form of FNO 2 ? (N is the central atom.)
A compound with a molar mass of about 42 g/mol contains 85.7% carbon and 14.3% hydrogen. What is its molecular structure?
The Lewis structure is made from three units, but the atoms must be rearranged:
Use the simulation to perform the following exercises for a two-atom molecule:
- Adjust the electronegativity value so the bond dipole is pointing toward B. Then determine what the electronegativity values must be to switch the dipole so that it points toward A.
- With a partial positive charge on A, turn on the electric field and describe what happens.
- (c) With a small partial negative charge on A, turn on the electric field and describe what happens.
- Reset all, and then with a large partial negative charge on A, turn on the electric field and describe what happens.
Use the simulation to perform the following exercises for a real molecule. You may need to rotate the molecules in three dimensions to see certain dipoles.
- Sketch the bond dipoles and molecular dipole (if any) for O 3. Explain your observations.
- Look at the bond dipoles for NH 3 . Use these dipoles to predict whether N or H is more electronegative.
- (c) Predict whether there should be a molecular dipole for NH 3 and, if so, in which direction it will point. Check the molecular dipole box to test your hypothesis.
The molecular dipole points away from the hydrogen atoms.
Use the Molecule Shape simulator to build a molecule. Starting with the central atom, click on the double bond to add one double bond. Then add one single bond and one lone pair. Rotate the molecule to observe the complete geometry. Name the electron group geometry and molecular structure and predict the bond angle. Then click the check boxes at the bottom and right of the simulator to check your answers.
Use the Molecule Shape simulator to explore real molecules. On the Real Molecules tab, select H 2 O. Switch between the “real” and “model” modes. Explain the difference observed.
The structures are very similar. In the model mode, each electron group occupies the same amount of space, so the bond angle is shown as 109.5°. In the “real” mode, the lone pairs are larger, causing the hydrogens to be compressed. This leads to the smaller angle of 104.5°.
Use the Molecule Shape simulator to explore real molecules. On the Real Molecules tab, select “model” mode and S 2 O. What is the model bond angle? Explain whether the “real” bond angle should be larger or smaller than the ideal model angle.


7.4: Social Institutions
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- Erika Gutierrez, Janét Hund, Shaheen Johnson, Carlos Ramos, Lisette Rodriguez, & Joy Tsuhako
- Long Beach City College, Cerritos College, & Saddleback College via ASCCC Open Educational Resources Initiative (OERI)
The social institutions of our culture also inform our socialization. Formal institutions—like schools, workplaces, religion and the government—teach people how to behave in and navigate these systems. Other institutions, like the media, contribute to socialization by inundating us with messages about norms and expectations. Chapter 4.3 discussed institutional discrimination , or discrimination that pervades the practices of whole institutions, such as housing, medical care, law enforcement, employment, and education. This section will dive deeper into the social institution of family, criminal justice system, religion, healthcare, education, economics, politics and the impact these institutions have on the lives of African Americans.
African American Family
Sociologist and author, Andrew Billingsley's (1992) , research on the African-American nuclear family has been divided into four parts that is used to show the differences in the family structure based on “gender, marital status, and the presence or absence of children, other relatives or non-relatives." These family sub-structures are divided up into three major structures: nuclear families, extended families, and augmented families.
The nuclear family structure has been defined as a married couple with children. This is the traditional norm for the composition of African-American families. Yet, in 1992, Billingsley documents that 25% of African-American families were nuclear families in comparison to 36% of all U.S. families. Almost 70 percent of Black children are born to unmarried parents.
The African-American segmented nuclear I (unmarried mother and children) and II (unmarried father and children) family structures are defined as a parent–child relationship. In 1992, 94% of African-American segmented nuclear families were composed of an unmarried mother and children. Glick's research found that single parent families are twice as prevalent in African-American families as they are in other races, and this gap continues to widen.
Billingsley's research continued with the African-American extended family structure, which is composed of primary members plus other relatives. Extended families have the same sub-structures as nuclear families, with the addition of grandparents, aunts, uncles, cousins and additional family members. In 1992, 47% of all African-American extended families were segmented extended family structures, compared to 12% of all other races combined. Billingsley's research shows that in the African-American family the extended relative is often the grandparents.
Billingsley's research revealed another type of African-American family, called the augmented family structure, which is a family composed of the primary members, plus non-relatives. Billingsley's case study found that this family structure accounted for 8% of Black families in 1990. This family structure is different from the traditional nuclear family discussed earlier, as it combines the nuclear and extended family units with non-relatives.
Billingsley introduced a new family structure that branches from the augmented family structure. The African-American population is starting to see a new structure known as a non-family household. This non-family household contains no relatives. According to Glick in 1992, 37% of all households in the United States were a non-family household, with more than half of this percentage being African-Americans.
Rise in Divorce Rates
For African Americans who do marry, the rate of divorce is higher than white Americans. While the trend is the same for both African Americans and white Americans, with at least half of marriages for the two groups ending in divorce, the rate of divorce tends to be consistently higher for African Americans. African Americans also tend to spend less time married than white Americans. Overall, African Americans are married at a later age, spend less time married, and are more likely to be divorced than white Americans.
The decline and low success rate of Black marriages is crucial for study because many African Americans achieve a middle-class status through marriage and the likelihood of children growing up in poverty is tripled for those in single-parent rather than two-parent homes. Some researchers suggest that the reason for the rise in divorce rates is the increasing acceptability of divorces. The decline in social stigma of divorce has led to a decrease in the number of legal barriers of getting a divorce, thus making it easier for couples to divorce.
Breakdown of the Black Family
According to data extracted from 1910 U.S. Census manuscripts, compared to white women, Black women were more likely to become teenage mothers, stay single and have marriage instability, and were thus much more likely to live in female-headed single-parent homes. This pattern has been known as Black matriarchy because of the observance of many households headed by women.
The breakdown of the Black family was first brought to national attention in 1965 by sociologist and later Democratic Senator Daniel Patrick Moynihan, in the groundbreaking Moynihan Report (also known as The Negro Family: The Case For National Action). Moynihan's report made the argument that the relative absence of nuclear families (those having both a married father and mother present) in Black America would greatly hinder further Black socio-economic progress.
The African American single parent family structure has historical roots dating back to 1880. A study of 1880 family structures in Philadelphia showed that three-quarters of Black families were nuclear families, composed of two parents and children. Data from U.S. Census reports reveal that between 1880 and 1960, married households consisting of two-parent homes were the most widespread form of African-American family structures. Although the most common, married households decreased over this time period. Single-parent homes, on the other hand, remained relatively stable until 1960, after which time they rose dramatically.
In the Harlem neighborhood of New York City in 1925, 85% of kin-related Black households had two parents. When Moynihan warned in his 1965 report on the coming destruction of the Black family, however, the out-of-wedlock birthrate had increased to 25% among the Black population. This figure continued to rise over time and in 1991, 68% of Black children were born outside of marriage. U.S. Census data from 2010 reveal that more African-American families consisted of single mothers than married households with both parents. In 2011, it was reported that 72% of Black babies were born to unmarried mothers. As of 2015, at 77.3 percent, Black Americans have the highest rate of non-marital births among native-born Americans.
In 2016, only 29% of African Americans were married, while 48% of all Americans were. Also, 50% of African Americans have never been married in contrast to 33% of all Americans. In 2016 just under half (48%) of Black women had never been married which is an increase from 44% in 2008 and 42.7% in 2005. Also in 2016, 15% percent of Black men were married to non-Black women which is up from 11% in 2010. Black women were the least likely to marry non-Black men at only 7% in 2017.
Non-marital births are far more common among Blacks than whites. In 2014, roughly seven-in-ten (71%) births to Black women occurred outside of marriage, compared with 29% of births to white women (Figure \(\PageIndex{1a}\)).
Black children are more than twice as likely as white children to be living with just one parent. More than half (54%) of Black children did so in 2014, compared with 19% of whites. This 35-percentage point difference marks a widening of the racial gap in children’s living arrangements. In 1970, 35% of Black children were living with only one parent, compared with 10% of white children (Figure \(\PageIndex{2b}\)).
The marriage rate has declined across racial and ethnic groups, but the drop has been particularly dramatic among Blacks. In 2014, some 35% of Black adults ages 25 and older were married, compared with 60% of whites. In 1970, this gap was considerably smaller: fully 60% of Blacks and 76% of whites were married at that time (Figure \(\PageIndex{2c}\)).
Structural barriers are often listed as the reason for the current trends in the African American family structure, specifically the decline in marriage rates. Imbalanced sex ratios have been cited as one of these barriers since the late nineteenth century, where Census data shows that in 1984, there were 99 Black males for every 100 Black females within the population. 2003 census data shows there are 91 Black males for every 100 females.
Criminal Justice System: Black Male Incarceration and Mortality
Let's also consider the link between the social institutions of family and the criminal justice system. Black male incarceration is often considered as one important explanation for the imbalanced sex ratios discussed earlier. Although Black males make up 6% of the population, they make up 50% of those who are incarcerated. This incarceration rate for Black males increased by a rate of more than four between the years of 1980 and 2003. The incarceration rate for African American males is 3,045 out of 100,000 compared to 465 per 100,000 white American males. In many areas around the country, the chance that Black males will be arrested and jailed at least once in their lifetime is extremely high. For Washington, D.C., this probability is between 80 and 90%.
Because Black males are incarcerated at six times the rate of white males, the skewed incarceration rates harm these Black males as well as their families and communities. Incarceration can affect former inmates and their future in society long after they leave prison. Those that have been incarcerated lose masculinity, as incarceration can affect a man's confirmation of his identity as a father and a breadwinner for the family. After being released from prison, efforts to reestablish or sustain connections and be active within the family are often unsuccessful. Incarceration can be damaging to familial ties and can have a negative effect on family relations and a man's sense of masculinity.
The New Jim Crow
The New Jim Crow: Mass Incarceration in the Age of Colorblindness is a book by Michelle Alexander , a civil rights litigator and legal scholar. Though the conventional point of view holds that systemic racial discrimination mostly ended with the civil rights movement reforms of the 1960s, Alexander posits that the U.S. criminal justice system uses the War on Drugs as a primary tool for enforcing traditional, as well as new modes of discrimination and oppression. These new modes of racism have led to not only the highest rate of incarceration in the world, but also a disproportionately large rate of imprisonment for African American men.
Alexander points out that mass incarceration is "a stunningly comprehensive and well-disguised system of racialized social control that functions in a manner strikingly similar to Jim Crow." The culmination of this social control is what Alexander calls a "racial caste system ," a type of stratification wherein people of color are kept in an inferior position. Its emergence, she believes, is a direct response to the Civil Rights Movement. It is because of this that Alexander argues for issues with mass incarceration to be addressed as issues of racial justice and civil rights. To approach these matters as anything but would be to fortify this new racial caste. Thus, Alexander aims to mobilize the civil rights community to move the incarceration issue to the forefront of its agenda and to provide factual information, data, arguments and a point of reference for those interested in pursuing the issue. Her broader goal is the revamping of the prevailing mentality regarding human rights, equality and equal opportunities in America, to prevent future cyclical recurrence of what she sees as “racial control under changing disguise”. According to the author, what has been altered since the collapse of Jim Crow is not so much the basic structure of US society, as the language used to justify its affairs. She argues that when people of color are disproportionately labeled as “criminals”, this allows the unleashing of a whole range of legal discrimination measures in employment, housing, education, public benefits, voting rights, jury duty, and so on.
Alexander argues that the War on Drugs has a devastating impact on inner city African American communities, on a scale entirely out of proportion to the actual dimensions of criminal activity taking place within these communities. During the past three decades, the US prison population exploded from 300,000 to more than two million, with the majority of the increase due to drug convictions. This led to the US having the world's highest incarceration rate. The US incarceration rate is eight times that of Germany, a comparatively developed large democracy. Alexander claims that the US is unparalleled in the world in focusing enforcement of federal drug laws on racial and ethnic minorities. In the capital city of Washington, D.C. three out of four young African American males are expected to serve time in prison. While studies show that quantitatively Americans of different races consume illegal drugs at similar rates, in some states Black men have been sent to prison on drug charges at rates twenty to fifty times those of white men. The proportion of African American men with some sort of criminal record approaches 80% in some major US cities, and they become marginalized, part of what Alexander calls "a growing and permanent "undercaste".
Religion
The range of descriptions of African American religious experiences has traditionally fallen between the sacred and the profane. Particularly, for African American religious experiences the Black Church has been viewed as the most sacred aspect of Black religious communities. Subsequently, the Black Church has been described as the driving force behind the agenda of Black leaders during the Civil Rights Movement. However, it was not the Black Church that was the defining attribute of African American religious experiences during the middle of the twentieth century; rather, it was a particular idea that many held most sacred. The way African Americans testified to their own experience can be described as a prophetic testimony : the notion of prophecy was the force that inspired many leaders to use their day-to-day experiences as testimonies to start a movement that went beyond accommodation with the goal of transformation. In this context, prophetic testimony must be examined through the lens of political theology alongside history. The category of political theology helps to emphasize the deep connection between faith (a theological claim) and the exercise of faith (a political claim). In other words, political theology combines pragmatic functions of faith with the way it is practiced.
Paradox in the Black Church
Paradox in the Black Church
Black Church institutions have been acknowledged as the center for social justice movements within Black communities. Yet whether it is through examining the classical period of the Civil Rights Movement or a look at modern day religious leaders, there has not been one specific way that Black communities have sought to liberate their identities from a world that has not often recognized their humanity. Past examples include the crusades of organizations such as the Nation of Islam and the Pan-African Movement, while the Black Lives Matter Movement is a current example. This has led to numerous paradoxical responses to both civil rights and social movements from Black religious organizations. The paradox that occurs across the spectrum of Black Church institutions is deeply rooted in the historical context from which the traditions have developed.
During the period of enslavement in the United States slave masters recognized that religion could be used as a form of social control, especially in Southern states. Slave owners allowed slaves to hear biblical scripture, but only in so far as it reinforced the narrative that required their subordination to their masters. Many slave owners realized that controlled religion could be used to make their slaves docile and subordinate. Slaves were typically allowed to have their own services where either a white overseer or another slave gave a sermon based on the guidance of the master. In other words, officially sanctioned Black churches were under the supervision of white pastors who used religion as a way to reinforce their social and political agenda. To further limit any form of autonomy in Black churches, laws were created that prevented slaves from assembling together for “worship” or for any other purpose between sunrises and sunsets, even with a white master present in many Southern states. The only exception to these rules occurred when the slave masters took their slaves to an ordained white minister who regularly conducted services. Furthermore, the influence of white masters on many Black Churches created a religious benevolence between slave and slave master that helped to keep intact the moral order that served to justify both the institution of slavery and the treatment of slaves. Slaveholders had a religious imperative to make money and to have a comfortable living, as long as they were faithful to God. Masters were supposed to take great interest in the slave’s security because it would benefit both the slave and the owner. They also had the responsibility of teaching the enslaved Black Americans good behavior and morality.
They believed that religious instruction of the Black slaves would promote both their morality and their religion. Black churches became the ideal institution to realize the creation of a Christian interracial community. In these communities, slave owners would benevolently rule over their slaves, who were presumed to be satisfied with their positions in life. This form of social control had some success with slaves. Most did not subscribe to the benevolent master motif that was impressed upon them, but the combination of various methods of oppression left many slaves in desperate need of hope from some source. Many who chose to challenge the dominant narrative had hope in a political freedom that was possible only in the afterlife. The language of the slave spirituals makes proclamations such as: “I'm gonna wait upon the Lord till my change comes.” This represents one polarity in which the Black Church was pulled. Indeed, this ideology continued well beyond the period of African enslavement and into the Civil Rights Movement era.
Health
Health Inequality
A deep connection between the field of medicine and the overall treatment and perception of African American extends back to the founding of this country. Proponents used pseudo-scientific (discussed in Chapter 1.2 as racialized science) ideas about the "natural" inferiority of Blacks to justify racism and slavery. In turn, these same forces led to a health inequality—with poor care from the medical field and higher rates of serious health issues—that persist in the present. African Americans have also faced lasting barriers in gaining employment and professional recognition in the healthcare field.
From the origins and continuation of health inequality to the fight to gain access to professional medical treatment, African American health and healthcare in U.S. history are interrelated issues. African American physicians, dentists, and nurses along with Black medical schools and hospitals have done pioneering work. While traditionally receiving less attention than issues like voting, housing, and education, the African American fight for healthcare is an important component of the Black freedom struggle, and a key aspect for understanding the current state of Black Americans.
This section is licensed CC BY-NC. Attribution: Slavery to Liberation: The African American Experience (Encompass) ( CC BY-NC 4.0 )
African American Health in Early U.S. History
African American health is inextricably linked to slavery. Physician and scholar Rodney G. Hood argues that health disparities can be traced back to the period of slavery and the origins of racism, an effect he calls the "slave health deficit." The enslavement of millions of African Americans had severe and lasting health impacts, both during the period of slavery and after. The initial period of enslavement may have been the most lethal. Historians estimate that as many as 50% of Africans died before leaving the continent during capture, the forced march to slave holding areas, or waiting in pens. Somewhere between 15-20% died during the Middle Passage across the Atlantic from the fifteenth through the nineteenth century. The mortality rate varied by place of origin, conditions in captivity and on the ship, and the point of destination. As many as 675,000 died during capture, captivity, or transportation to this country. Of the 450,000 Africans who made it to the U.S., an additional 4.3% died in the period between arrival and sale, and as many as 25% perished during the "acclimation period" of their first eighteen months as they adjusted to new locations, climates, and diseases.
Enslaved individuals suffered from significant health problems. The Black infant and childhood mortality rate was double the rate for whites. Over half of all Black children were born severely underweight due to the poor treatment and lack of nutrition for pregnant slaves; many women miscarried or gave birth to stillborn babies. On average, Black mothers could nurse for only four months, compared to eight months for white babies. Early weaning, horrid living conditions, and lack of nutrition led to more than 50% of Black infants dying before the age of one.
The field of medicine both justified the poor treatment of African Americans and contributed to their health problems. Building on the writings of white intellectuals going back to at least the Greeks, leading American scientists and physicians categorized African Americans as biologically inferior and less intelligent, or even sub-human. By the early 1800s, proponents of slavery used this pseudo-scientific argument to justify slavery. Defenders of slavery further argued that Africans were more genetically predisposed to work in the fields than whites. Thomas Jefferson advocated this position in his influential Notes on the State of Virginia (1805). While he concluded that enslaved Africans were "inferior to the whites in the endowments both of body and mind," Jefferson argued that they possessed some qualities that made them genetically designed to labor, notably that they "seem to require less sleep" and were "more tolerant of heat." Physicians perpetuated the belief that Africans also had resistance or immunity to diseases like yellow fever.
The inequality in access to healthcare and the poor treatment by physicians in this period marked the beginning of a healthcare system based on racial discrimination. The view of African Americans as inferior and "less worthy" meant that few received proper medical care for curable afflictions. In some ways, free Blacks faced worse healthcare, with little access due to high rates of poverty and physicians who refused to treat Black patients. A two-tiered healthcare system—with greater access and treatment for whites—persisted for much of American history.
Medical Exploitation
Despite gains due to legislation, many African Americans remained distrustful of the government's involvement in healthcare. In the early twentieth century, the government funded forced sterilization programs in 32 states for tens of thousands of women, primarily people of color. Originating in the late nineteenth century, the eugenics movement spread in the U.S. starting in the 1900s. Eugenics was based on the concept that selective breeding should be encouraged, with government involvement, to improve society. Supported by funding from leading organizations like the Carnegie and Rockefeller foundations, scientists from top universities carried out pseudo-scientific research that demonstrated supposed negative genetic traits of certain groups that should not be allowed to reproduce: the mentally ill or disabled, those deemed sexually deviant, criminals, immigrants, the indigent, and minorities. Some doctors actively engaged in eugenicide , killing patients or willfully neglecting them—often newborns—until they died.
Forced sterilization became the most mainstream manifestation of eugenics, with states adopting forced sterilization laws in the first decade of the twentieth century. Although masked as progressive reform (to produce the most superior citizens and to reduce government spending on providing for the "unworthy") and supported by public health advocates, scientists, physicians, and politicians, forced sterilization was a product of racism and xenophobia (xenophobia was discussed earlier in Chapter 3.5 ). In many ways, proponents promoted forced sterilization similar to the ways they advocated residential segregation (i.e., African Americans should be kept out of white neighborhoods to prevent the spread of disease) or anti-miscegenation (i.e., interracial marriage and children would produce "inferior," mixed race children, damaging to white purity). The Nazis partially modeled their own policies of sterilization and eugenicide in the 1930s and 1940s on American practices.
Eighteen Southern states adopted sterilization laws and often used them to target African American women. In 1964, Mississippi Freedom Democratic Party leader and voting rights advocate Fannie Lou Hamer spoke of her own experience. In 1961, Hamer underwent surgery in Mississippi for a uterine tumor. During surgery, and without her consent, the operating physician performed an unnecessary hysterectomy. Hamer highlighted the commonality of the procedure, which she dubbed a "Mississippi appendectomy," and estimated that physicians at the hospital, without consent and with no medical need, sterilized approximately 60% of Black female patients.
The Black Panther Party's health program further reflected the distrust of medical institutions. As detailed earlier, physicians used enslaved African Americans for medical experiments. Hospitals and prisons continued this practice after slavery ended, and medical colleges stole African American cadavers for student training. Perhaps the most famous example of medical exploitation was the Tuskegee Experiment , started by the U.S. Public Health Service in 1932. The program recruited 600 Black men—399 with syphilis, and 201 not infected—for a study on the effects of the disease. Administrators promised free medical treatment for participants. However, physicians did not inform the men of the purpose of the study and did not treat the individuals who had syphilis, even after penicillin was discovered as a cure in 1947. In 1972, the Associated Press reported on the story, leading to a public outcry and investigations. Recent research has demonstrated that the history of medical exploitation, particularly the Tuskegee Experiment, has led African Americans to be more distrustful of doctors and less likely to use healthcare services, contributing to the higher mortality rare.
Continuing Health Inequality
While the immediate years after integration saw some health gains for African Americans, particularly for those who previously had no access at all, improvements largely stagnated after 1975. Starting in the 1980s, Black mortality began to increase again, and African American life expectancy declined. With white flight to the suburbs, Black residents were increasingly concentrated in urban cores with underfunded and lower-quality healthcare.
In the face of continued health disparity, African American groups again provided their own medical services. Leonidas H. Berry founded an organization named the Flying Black Medics. Sponsored by the Methodist Episcopal Church and local community groups, the group began flights in 1970 from Chicago to Cairo, Illinois, providing free medical care and supplies to poor African Americans. In the late 1960s, the Black Panther Party became involved in healthcare. The national organization required all chapters to provide health clinics due to continued health discrimination and inequality. The Panthers also launched a sickle cell anemia awareness campaign, providing education and free screening for the disease, which the organization felt was understudied and underfunded as it disproportionately affected African Americans.
In the 1980s, the increase in the Black mortality rate also corresponded with the decreased funding for hospitals that predominantly served the African American community. State aid declined dramatically, particularly with the economic recession. The number of Black hospitals rapidly plummeted as a result. From 1961 to 1988, forty-nine Black hospitals closed, including Chicago's Provident Hospital, the first Black-operated hospital in the country.
Contemporary Health Disparities Experienced by African Americans
Health inequality persists in the U.S. The Centers for Disease Control (CDC) and Prevention found that African Americans have a significantly shorter life expectancy (75.1 years) than whites (78.7). African Americans suffer from higher rates of illness and health problems; the CDC estimates that 13.6% of African Americans are in poor health compared to 9.5% of whites. The overall mortality rate has dropped for all races in the past two decades, driven by declining deaths from cancer, heart attacks, and strokes. However, African Americans still have a mortality rate 16% higher than whites (down from 33% in 1999), and are more likely to die at every age. The discrepancy is particularly notable in infant mortality—a rate of 10.93 per 1,000 for Blacks and 4.89 per 1,000 for whites—and in maternal deaths with a rate of 43.5 Black deaths per 100,000 live births compared to 12.7 white deaths per 100,000 live births. The mortality rates for African American males are also typically higher than they are for African American females. This is another explanation for the imbalanced sex ratios mentioned earlier in the discussion on the African American Family. Between 1980 and 2003, 4,744 to 27,141 more African American males died annually than African American females. This higher mortality rate helps to explain the low marriage rates for many African American females who cannot find Black partners.
According to the Centers for Disease Control and Prevention (CDC), the following were the leading causes of death of Black men in 2017:
| Non-Hispanic Black, Male, All ages | Percent |
|---|---|
| 1) Heart disease | 23.7% |
| 2) Cancer | 20.2% |
| 3) Unintentional injuries | 7.9% |
| 4) Homicide | 5.0% |
| 5) Stroke | 4.9% |
| 6) Diabetes | 4.3% |
| 7) Chronic lower respiratory diseases | 3.2% |
| 8) Kidney disease | 2.6% |
| 9) Septicemia | 1.7% |
| 10) Hypertension | 1.6% |
For young Black men between the ages of 15 and 44, the number one cause of death in 2017 was homicide. Strikingly, the number six cause of death for Black men in this age range is police violence.
According to the Centers for Disease Control and Prevention (CDC), the following were the leading causes of death of Black women in 2016:
| Non-Hispanic Black, Female, All ages | Percent |
|---|---|
| 1) Heart disease | 23.1% |
| 2) Cancer | 21.8% |
| 3) Stroke | 6.4% |
| 4) Diabetes | 4.5% |
| 5) Alzheimer’s disease | 3.9% |
| 6) Unintentional injuries | 3.6% |
| 7) Chronic lower respiratory diseases | 3.4% |
| 8) Kidney disease | 3.1% |
| 9) Septicemia | 2.3% |
| 10) Hypertension | 2.0% |
Health inequality reflects multiple factors: higher rates of unemployment, obesity, and poverty as well as lower rates of home ownership, education, and wealth. African Americans also continue to have less access to healthcare : 11.2% under the age of 65 do not have healthcare, compared to 7.5% of whites. Researchers have also demonstrated that racial discrimination, including from the healthcare system itself, also negatively impacts health. Inequality continues in the medical profession, too. While making up 12% of the overall population, less than 6% of physicians and surgeons are Black.
The roots of health inequality date back to the beginning of this country. Treated as racially inferior, neglected or excluded by white healthcare systems and as the victims of systematic and institutionalized racism and segregation, African Americans have suffered higher rates of disease and mortality than white Americans throughout this country's history. African Americans have fought for increased access; provided care for themselves in various forms, from enslaved midwives to Black hospitals; and made important contributions to the medical field. However, the historical vestiges of a two-tiered healthcare system remain as deeply entrenched as other aspects of structural/system racism (defined in Chapter 4.4 ).
Education
Increasingly, a college degree is the key to financial well-being, while the value of a high school diploma has diminished markedly over time. Since the 1960s, rates of college graduation have increased significantly for all major racial and ethnic groups, though large gaps persist as Blacks still trail whites in college completion, according to the 2016 Pew Research Center report (Figure \(\PageIndex{8}\)).
The 2016 Pew Research Center analysis of U.S. Census Bureau data shows that while the income gap between Black and white college-degree earners is narrower than those with less education, it still remains significant. The median adjusted household income among Black householders with at least a bachelor’s degree was $82,300 in 2014, compared with $106,600 among white householders with the same level of education.
Education alone also does not close unemployment gaps between Blacks and whites. The unemployment rate for Blacks in 2015 was roughly double that of whites across all educational categories, according to the 2016 Pew Research Center’s analysis of Census Bureau data.
Economics
Black households have only 10 cents in wealth for every dollar held by white households (Pew Research Center, 2017). In 2016, the median wealth of non-Hispanic white households was $171,000. That’s 10 times the wealth of Black households ($17,100) – which reflects a larger gap than in 2007. The Great Recession of 2007-2009 triggered a stark decline in wealth for U.S. families and further widened the already large wealth gap between white and Black households. Yet the Black-to-white wealth gap has evolved differently for families at different income levels, according to a Pew Research Center analysis of Federal Reserve data . The wealth gap increased between middle-income Black and white families, but shrank between lower-income Black and white families from 2007 to 2016. Much of the reduction in the wealth gap among lower-income families was driven by a sharp decrease in wealth for whites Figure \(\PageIndex{10}\).
Blacks are more than twice as likely as whites to live in poverty ( Income and Poverty in the United States: 2014 ) . In 2014, about a quarter (26%) of Blacks were poor, compared with 10% of whites. The Black-white poverty gap has narrowed somewhat since the mid-1970s, when 30% of Blacks were living below the poverty line – a proportion nearly four times the share of whites living in poverty (8%).
Figure \(\PageIndex{11}\): Blacks are still more than twice as likely as Whites to be poor, despite narrowing of poverty gap. ( Used with permission ; On Views of Race and Inequality, Blacks and whites Are Worlds Apart . Pew Research Center , Washington, D.C. (2016))
Politics
Many Blacks view political representation as a potential catalyst for increased racial equality, according to a 2016 Pew Research Center survey . Roughly four-in-ten Black adults (38%) said that working to get more Black people elected to office would be a very effective tactic for groups striving to help Blacks achieve equality.
Following Reconstruction till 1900, large numbers of Black Americans were elected to political office at the local, state and national levels. These elected officials included: Hiram Revels, first Black U.S. Senator (who was also a member of the Lumbee Nation) and Frederick Douglass, appointed President of the Freedman's Saving Bank and diplomat to the Dominican Republic. As discussed in Chapter 7.2, the Jim Crow era and backlash against the Black middle class all but contributed to the absence of Black elected officials for the better part of the 20th century. Only 11 Black senators have been elected in all of U.S. history, with the most recent being Reverand Raphael Warnock, who won a highly contested runoff in Georgia in 2021. Barack Obama, the most famous of these was elected as the first Black President. Shirley Chisholm was the first African American to run for President in 1972; in her bid to run on the Democratic Party ticket, she announced, “I am not the candidate of Black America, although I am Black and proud. I am not the candidate of the women’s movement in this country, although I am a woman, and equally proud of that... I am the candidate of the people of America.”
Voting
In 1870, the 15th Amendment was ratified, guaranteeing African American (men) the right to vote; however, challenges to this right included the poll tax, the grandfather clause, and literacy tests which disenfranchised countless Black voters during the Jim Crow era encompassing most of the 20th century. The 19th Amendment was passed in 1920, guaranteeing suffrage for all women, including Black women. Yet, the struggle to vote continued. The Civil Rights Movement championed voting rights in campaigns such Freedom Summer (Mississippi) and the Selma to Montgomery (Alabama) March, registering thousands of Black voters. Fannie Lou Hamer, an organizer of Freedom Summer and co-founder of the Mississippi Freedom Democratic Party, went to the 1964 Democratic Party Convention, attempting to be part of the official delegation, gave a blistering speech with details about voter registration suppression - which was later televised nationally and gained further support for the voting rights for Black Americans. President Lyndon Johnson signed into law the Voting Rights Act of 1965, prohibiting racial discrimination in voting. While Congress amended the Act to extend its enforcement, in the last decade, significant challenges to the enforcement have been granted by the U.S. Supreme Court, thereby negating the strength of the Voting Rights Act. Additionally, Southern states, such as Florida, Alabama, Kentucky, Mississippi, Tennessee, and Virginia, deny convicted felons the right to ever vote - even after they have served their sentence, a policy which disproportionately impacts the Black population which has higher incarceration rates than other race-ethnic groups. According to the Sentencing Project (2016), one in 13 African Americans of voting age is disenfranchised, which is four times greater than non-African Americans voters. Further, over 7.4 percent of the adult African American population is disenfranchised compared to 1.8 percent of the non-African American population (Sentencing Project, 2016). In Florida, Kentucky, Tennessee, and Virginia, more than 1 in 5 African Ameicans is a disenfranchised voter due to a felony conviction. With so many disenfrancised voters, the struggle for voting rights for Black voters is far from over. Yet, through the efforts of voting rights activists such as Stacey Abrams, who co-founded the New Georgia Project in 2014 and registered more than 500,000 new voters, the state of Georgia shifted to a predominantly Democratic state in 2020, helping the Biden-Harris ticket to clench the 2020 Presidential election.
Contributors and Attributions
Content on this page has multiple licenses. Everything is CC BY-SA other than Paradox in the Black Church and Health Inequality which are CC BY-NC.
- Johnson, Shaheen. (Long Beach City College)
- Hund, Janét. (Long Beach City College)
- Slavery to Liberation: The African American Experience (Encompass) ( CC BY-NC 4.0 ) (Contributed to: Paradox in the Black Church and Health Inequality)
- African-American Family Structure (Wikipedia) ( CC BY-SA 3.0 )
- The New Jim Crow (Wikipedia) ( CC BY-SA 3.0 )
Works Cited
- Anderson, M. (2016, July 16). Blacks with college experience more likely to say they faced discrimination. Pew Research Center .
- Billingsley, A. (1992). Climbing Jacob's Ladder . New York, NY: Simon & Schuster.
- Brown, T. & Patterson, E. (2019). Wounds from incarceration that never heal. The New Republic .
- Byrd, W. M. & Clayton, L.A. (1992). An American health dilemma: a history of Blacks in the health system. Journal of the National Medical Association , 84 (2), 189.
- Centers for Disease Control and Prevention. (2020). LastStats - Health of Black or African American population .
- Daniel P.M. (1965). The Negro Family: The Case for National Action , Washington, D.C., Office of Policy Planning and Research, U.S. Department of Labor.
- Digital History. (2016). What was life like under slavery. Digital History.
- Dixon, P. (2009). Marriage among African Americans: What does the research reveal? Journal of African American Studies . 13 (1): 29–46.
- Dyer, W.M. (2005). Prison fathers, and identity: A theory of how incarceration affects men's paternal identity. Fathering: A Journal of Theory, Research, and Practice About Men as Fathers . 3 (3): 201–219.
- Fogel, R.W. (1994). Without Consent or Contract: The Rise and Fall of American Slavery. New York, NY: WW Norton & Company.
- Gates, Jr., H.L. (2014). How many slaves landed in the U.S. T h e Root.
- Paul C. Glick, ed. by Harriette Pipes McAdoo (1997). Black families (3rd ed.). Thousand Oaks, Calif. [u.a.]: Sage. p. 119.
- Herbert C.C. (2007). African American Slave Medicine: Herbal and Non-Herbal Treatments. Lanham, MD: Lexington Books.
- Heron, M. (2018). Deaths: leading causes for 2016. National Vital Statistics Report, US Department of Health and Human Services.
- Hershberg, T. (1971). Free Blacks in antebellum Philadelphia: A study of ex-slaves, freeborn, and socioeconomic decline. Journal of Social History , 183-209.
- Hood, R.G. (2001). The" slave health deficit:" The case for reparations to bring health parity to African Americans. Journal of the National Medical Association , 93 (1),
- Klein, H.S., Engerman, S.L., Haines, R., & Shlomowitz, R. (2001). Transoceanic mortality: The slave trade in comparative perspective. The William and Mary Quarterly , 58 (1), 93-118.
- Kochhar, R. & Cilluffo. A. (2017). How wealth inequality has changed in the U.S. since the great recession, by race, ethnicity and income. Pew Research Center .
- McAdoo, P. (1997). Black F amilies. 3rd ed.. Thousand Oaks, CA.
- Mintz, S. (2013). Childhood and transatlantic slavery. Children & Youth in History.
- Moynihan, Daniel P. The Negro Family: The Case for National Action , Washington, D.C., Office of Policy Planning and Research, U.S. Department of Labor, 1965.
- Morgan, S.,McDaniel, A., Miller, A.T., & Preston, S.H. (1993). Racial differences in household and family structure at the turn of the century. American Journal of Sociology. 98 (4): 799–828.
- Pew Research Center . (2016). On views of race and inequality, Blacks and whites are worlds apart.


15.5: Analyzing a Project
Learning Outcomes
- Analyze a possible replacement projects to determine if it should be implemented
Let’s assume you, as a manager are presented with two options for projects, and you need to decide which one to implement if any. You have been tasked with analyzing them to determine which may be a good fit for your company, and which one will bring the greatest financial impact to company profits.
This task can seem daunting at first, especially if the options are diverse. Once we have screened all potential projects to make sure they meet the company’s minimum requirements to be considered, we can then rank them by preference before deciding. This process is used when there are limited funds, so all potential options cannot be implemented, or when only one project or piece of equipment would be needed. It may also be used to determine which project to implement first. So even if funds exist to implement more than one, ranking them in order of profitability is important in making capital budgeting decision.
So if funds are limited and only one option can be chosen, using either the internal rate of return (IRR) method or the net present value (NPV) method will yield the best results. Actually, do them both! If they conflict, the NPV method will probably be more reliable.
Using the IRR method, if one project has an IRR of 18% and a second project only has an IRR of 12%, then choosing the higher internal rate of return makes the most sense, right? When using the NPV method we need to adjust for differences in the initial investment of the project to be comparing apples to apples. We need to figure out what the project’s profitability index is, based on the initial investment amounts. Let’s look at an example:
| Hupana Running Company — Which Choice?? | ||
| Project | ||
| Stitcher | Sole Gluer | |
| Initial investment required | $25,000 | $15,000 |
| Present value of cash inflows | $20,000 | $10,000 |
| Net present value | $5,000 | $5,000 |
So back to Hupana again. They have limited funds and can choose to either purchase a stitcher or a sole gluer this year, but not both. Both pieces of equipment have the same net present value, but what is the project profitability for each choice?
Project profitability index = net present value of the project/initial investment required
| Hupana Running Company | ||
| Project | ||
| Stitcher | Sole Gluer | |
| Net present value | 5000 | 5000 |
| Initial investment required | 25000 | 15000 |
| Project profitability index | 20.00% | 33.33% |
So which one would we pick? The one with the higher profitability index, right? So, the sole gluer it is! Maybe Hupana can revisit the stitcher when they have additional funds!
Practice Questions


3.6: Notes
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- Last updated
- Save as PDF
- John T. Caldwell
- University of California Press
1 Allen Scott, On Hollywood (Princeton, NJ: Princeton University Press, 2005); and Toby Miller, Nitin Govil, John McMurria, and Richard Maxwell, Global Hollywood (London: British Film Institute, 2001).
2 Vicki Mayer, Below the Line (Durham, NC: Duke University Press, 2011); and Matt Stahl, Unfree Masters (Durham, NC: Duke University Press, 2013).
3 John Thornton Caldwell, Televisuality: Style, Crisis, and Authority in American Television (New Brunswick, NJ: Rutgers University Press, 1995); and John Thornton Caldwell, Production Culture: Industrial Reflexivity and Critical Practice in Film and Television (Durham, NC: Duke University Press, 2008).
4 Henry Jenkins, Convergence Culture (New York: New York University Press, 2006).
5 This is a play on Henry Jenkins, Spreadable Media (New York: New York University Press, 2013).
6 John Caldwell, “Para-Industry,” Cinema Journal 52.3. (Spring 2013): 157–165.
7 Scott, On Hollywood ; and Michael Curtin, Playing to the World’s Biggest Audience (Berkeley: University of California Press, 2007).
8 John Caldwell, “Convergence Television: Aggregating Form and Repurposing Content in the Culture of Conglomeration,” in Television after TV , ed. Lynn Spigel (Durham, NC: Duke University Press, 2004), 41–74.
9 By contrast, screenwriters still write spec scripts for film without promise of payment, yet continue maintaining “long-odds” hope that someone might buy script to make a movie.
10 See Erin Hill, “Women’s Work: Feminized Labor in Hollywood, 1930–1948” PhD diss., UCLA, 2014.
11 One of the best explorations of cross-cultural spec-mediation is Aynne Kokas, “Shot in Shanghai: Western Film Co-Production in Post-WTO Mainland China,” PhD diss., UCLA, 2012.
12 See example of crowd-sourced online-to-feature film project, Life in a Day . YouTube solicited thousands of user-shot videos to make its feature project. When the resulting aggregate project was screened online, then shown as a feature film in festivals, the project was boldly hyped as a “Ridley Scott Production,” clearly erasing its utopian collectivity.
13 See John Caldwell, Televisuality (New Brunswick, NJ: Rutgers University Press, 1995); Anna Everett and John Caldwell, eds., New Media (New York: Routledge, 2003); and John Caldwell, Production Culture (Durham, NC: Duke University Press, 2008)


11.1: Introduction
Routine prenatal care begins at the first prenatal visit and continues throughout the 280 days (40 weeks) of pregnancy. It involves nursing interventions based on the nurse’s assessment of the family. The purpose of prenatal care is to gather assessment data at each prenatal visit, to analyze the data to ensure there are no factors placing the fetus or pregnant person at risk for complications, and when complications are diagnosed, to monitor the pregnancy more closely for a positive patient and fetal outcome. Registered nurses are part of the prenatal health-care team in county public health departments, community health centers and clinics, and provider private practices, providing education regarding the antepartum, intrapartum, and postpartum periods as well as newborn and infant care.


3.3: Disease Risk and Nutrition
Nutrition and Health Are Closely Related
Over the past century, essential nutrient deficiencies have dramatically decreased, many infectious diseases have been conquered, and the majority of the U.S. population can now anticipate a long and productive life. However, as infectious disease rates have dropped, the rates of noncommunicable diseases—specifically, chronic diet-related diseases—have risen, due in part to changes in lifestyle behaviors.
A history of poor eating and physical activity patterns have a cumulative effect and have contributed to significant nutrition- and physical activity-related health challenges that now face the U.S. population. About half of all American adults—117 million individuals—have one or more preventable chronic diseases, many of which are related to poor quality eating patterns and physical inactivity. These include cardiovascular disease, high blood pressure, type 2 diabetes, some cancers, and poor bone health.
More than two-thirds of adults and nearly one-third of children and youth are overweight or obese. These high rates of overweight and obesity and chronic disease have persisted for more than two decades and come not only with increased health risks, but also at high cost. In 2008, the medical costs associated with obesity were estimated to be $147 billion. In 2012, the total estimated cost of diagnosed diabetes was $245 billion, including $176 billion in direct medical costs and $69 billion in decreased productivity.
Type 2 Diabetes
Diabetes is a disease in which blood glucose levels are above normal. Most of the food we eat is turned into glucose, or sugar, for our bodies to use for energy. The pancreas, an organ that lies near the stomach, makes a hormone called insulin to help glucose get into the cells of our bodies. When you have diabetes, your body either doesn’t make enough insulin or can’t use its own insulin as well as it should. This causes sugar to build up in your blood.
Diabetes can cause serious health complications including heart disease, blindness, kidney failure, and lower-extremity amputations.
What is prediabetes?
Prediabetes is when the amount of glucose in your blood is above normal yet not high enough to be called diabetes. With prediabetes, your chances of getting type 2 diabetes, heart disease, and stroke are higher. With some weight loss and moderate physical activity, you can delay or prevent type 2 diabetes. You can even return to normal glucose levels, possibly without taking any medicines.
What are the signs and symptoms of diabetes?
The signs and symptoms of diabetes are:
- being very thirsty
- urinating often
- feeling very hungry
- feeling very tired
- losing weight without trying
- sores that heal slowly
- dry, itchy skin
- feelings of pins and needles in your feet
- losing feeling in your feet
- blurry eyesight
Some people with diabetes don’t have any of these signs or symptoms. The only way to know if you have diabetes is to have your doctor do a blood test.
Click here to see a Snapshot of Diabetes in the United States
.
Contributors and Attributions
Public domain content
- Nutrition and Health Are Closely Related. Authored by : Office of Disease Prevention and Health Promotion. Provided by : U.S. Department of Health and Human Services. Located at : https://health.gov/dietaryguidelines/2015/guidelines/introduction/nutrition-and-health-are-closely-related/#table-i-1 . License : Public Domain: No Known Copyright
- Type 2 Diabetes. Authored by : Centers for Disease Control and Prevention. Located at : http://www.cdc.gov/diabetes/basics/diabetes.html . License : Public Domain: No Known Copyright
- Prediabetes. Authored by : National Institute of Diabetes and Digestive and Kidney Diseases. Provided by : National Institutes of Health. Located at : https://www.niddk.nih.gov/health-information/diabetes/types . License : Public Domain: No Known Copyright
- Stoplight image. Authored by : NIDDK Image Library. Provided by : NIH. Located at : catalog.niddk.nih.gov/catalo...il.cfm?id=1331. License : Public Domain: No Known Copyright
- Image: main Symptoms of Diabetes. Authored by Mikael Häggström. Provided by Wikimedia. Located at: https://commons.wikimedia.org/wiki/File:Main_symptoms_of_diabetes.png License : Public Domain: No Known Copyright


4.2: Business Models
A business model is a general outline of the transactions needed for your idea to make a profit. The most basic business model involves simply producing a product or service and selling it directly to customers. The company makes a profit if revenues are greater than production and business costs.
Business models are goal-driven
When developing your business model, clearly define the type of business you are pursuing and your goals for your business venture. Once you have a well-defined business idea and specific goals, you can establish the method by which you are going to make your profit.
First, identify your venture type. Is it a product, a service, or a business? If it’s a business, is it a service business or a product business? Is it a lifestyle business or a high growth business? A lifestyle business prioritizes lifestyle issues such as independence, location, and hours. A high-growth business gives priority to growth, expansion, and money back to investors.
If you have an idea for a product, do you have the means to produce and sell this product or do you plan to license it to another company? Ask yourself if your team is capable of getting the product or service to market. If not, who will help you, and how will you make money using their help?
Some model models
Your business model generically defines the product or business you are proposing, your customers, and the transaction mechanism(s) that will allow you to make money. This is an important step before you begin creating your formal business plan. Your business plan will describe your model in more detail.
Subscription-based and advertisement-based models are examples of business models found both on- and off-line. Many companies combine two or more business models or create their own unique model.
In a subscription-based business model, the provider charges a fee for access to the service. An example of this is Consumer Reports magazine. Consumer Reports relies solely on its subscription sales. It can do this because it carries a well-known brand name, and provides high quality print and online content, for which people are willing to pay.
An exclusively advertisement-based model provides free content to attract users, and is financially supported by advertisers. Network television is the most obvious model. The more successful a show is at attracting eyes, the more advertisers are willing to pay. Another example of an advertising-based business model, Yahoo!, provides free access to useful online resources. Users accept the presence of advertisements throughout the Yahoo! site. (Note: Yahoo! is gradually incorporating more subscription-based services.)
A licensing model is used by most software companies and some specialty product companies to create products, then license them to other companies. The Bagel Biter in Northampton, MA manufactures a bagel-slicing machine, and gets others to sell it in their catalogs and stores. This model works for companies that have a narrow product line and can sell a limited number of units.
What happened to the dotcoms?
The most talked about business models in recent memory are based in e-commerce. Dotcoms held the promise of unlimited wealth production with minimal overhead. Most businesses today offer a way for consumers to access their product or service online, but the surge of exclusively online businesses has faded. Many sites that thrived in the late 90s are now defunct. What happened?
Paul A. Greenberg writes, “Many of the young dot-commers rejected traditional business models in favor of rampant spending, over-extension of debt and high-risk ventures backed by adventurous investors.”1 Colin Duguid and Caroline Tresman add, “A solid business is not maintained just by its shop front or by its product, but by basic business skills through its management and staff. If the management has little or no skills but ‘a great idea,’ how long would it last and could they see what would otherwise be simple business problems?”
To survive, plan your venture and evaluate your team’s financial capabilities as well as your business management experience. Also, analyze the market to determine if your model can make a profit. Lastly make sure that you are aware of your competitors and your possible risks (more on these issues in the section 2, “The Market”).
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About business models
From “The Truth about Internet Business Models,” by Jeffrey F. Rayport. “A business model is quite simple: it is a brief statement of how an idea actually becomes a business that makes money. It tells who pays, how much, and how often. The same product or service may be brought to market with several business models..” From “Anatomy of a Business Model” by Steve Robbins.
Differentiating your business: A real life example
“We build, host, and manage private-label online directories for leading publishers and portals. We sell companies enhanced subscriptions (listings in the directories), and access to sales leads, or RFPs (Requests for Proposals) on behalf of those directories, and return a portion of that revenue to the partner. The partner gets a no-cost revenue stream; we get to sell a product with an established brand name on it, and keep a large portion of that revenue, as opposed to having to build our own brand. So, this is how we’ve differentiated ourselves in the market: essentially, by not caring if people (other than partners) know who we are. It’s worked up to this point. And all those dotcom companies that raised, in some cases, hundreds of millions, to establish a brand name, are now out of business. So we’re happy we embarked on the ego-less business model of what’s termed Application Service Provider (ASP).” “In the most basic sense, a business model is the method of doing business by which a company can sustain itself—that is, generate revenue. The business model spells out how a company makes money by specifying where it is positioned in the value chain.” From “Business Models on the Web” by Michael Rappa. |