22.A: Review Questions-Medical, first-aid and bloodborne pathogens
Complete as directed.
True or False: (Circle Letter)
- Employers are required to render first aid to injured employees. T or F
- Rendering first aid includes providing for emergency services and response. T or F
- Only small employers are required to have first aid kits. T or F
- If employees are exposed to caustics or hazardous materials emergency wash stations must be available. T or F
- Setting a broken bone is considered first aid. T or F
- Applying a cold or hot compress is considered medical treatment. T or F
- An ECP is required of all employers. T or F
- Employees exposed to OPIM must wear PPE. T or F
- If an employee refuses hepatitis vaccine the employer does not have to medically monitor the employee. T or F
- Exposed employees must receive post exposure counseling. T of F.


15.E: Genes and Proteins (Exercises)
15.1: The Genetic Code
Review Questions
The AUC and AUA codons in mRNA both specify isoleucine. What feature of the genetic code explains this?
- complementarity
- nonsense codons
- universality
- degeneracy
- Answer
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D
How many nucleotides are in 12 mRNA codons?
- 12
- 24
- 36
- 48
- Answer
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C
Free Response
Imagine if there were 200 commonly occurring amino acids instead of 20. Given what you know about the genetic code, what would be the shortest possible codon length? Explain.
- Answer
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For 200 commonly occurring amino acids, codons consisting of four types of nucleotides would have to be at least four nucleotides long, because 4 4 = 256. There would be much less degeneracy in this case.
Discuss how degeneracy of the genetic code makes cells more robust to mutations.
- Answer
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Codons that specify the same amino acid typically only differ by one nucleotide. In addition, amino acids with chemically similar side chains are encoded by similar codons. This nuance of the genetic code ensures that a single-nucleotide substitution mutation might either specify the same amino acid and have no effect, or may specify a similar amino acid, preventing the protein from being rendered completely nonfunctional.
15.2: Prokaryotic Transcription
Review Questions
Which subunit of the E. coli polymerase confers specificity to transcription?
- α
- β
- β'
- σ
- Answer
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D
The -10 and -35 regions of prokaryotic promoters are called consensus sequences because ________.
- they are identical in all bacterial species
- they are similar in all bacterial species
- they exist in all organisms
- they have the same function in all organisms
- Answer
-
B
Free Response
If mRNA is complementary to the DNA template strand and the DNA template strand is complementary to the DNA nontemplate strand, then why are base sequences of mRNA and the DNA nontemplate strand not identical? Could they ever be?
- Answer
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DNA is different from RNA in that T nucleotides in DNA are replaced with U nucleotides in RNA. Therefore, they could never be identical in base sequence.
In your own words, describe the difference between rho-dependent and rho-independent termination of transcription in prokaryotes.
- Answer
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Rho-dependent termination is controlled by the rho protein, which tracks along behind the polymerase on the growing mRNA chain. Near the end of the gene, the polymerase stalls at a run of G nucleotides on the DNA template. The rho protein collides with the polymerase and releases mRNA from the transcription bubble. Rho-independent termination is controlled by specific sequences in the DNA template strand. As the polymerase nears the end of the gene being transcribed, it encounters a region rich in C–G nucleotides. This creates an mRNA hairpin that causes the polymerase to stall right as it begins to transcribe a region rich in A–T nucleotides. Because A–U bonds are less thermostable, the core enzyme falls away.
15.3: Eukaryotic Transcription
Review Questions
Which feature of promoters can be found in both prokaryotes and eukaryotes?
- GC box
- TATA box
- octamer box
- -10 and -35 sequences
- Answer
-
B
What transcripts will be most affected by low levels of α-amanitin?
- 18S and 28S rRNAs
- pre-mRNAs
- 5S rRNAs and tRNAs
- other small nuclear RNAs
- Answer
-
B
15.4: RNA Processing in Eukaryotes
Review Questions
Which pre-mRNA processing step is important for initiating translation?
- poly-A tail
- RNA editing
- splicing
- 7-methylguanosine cap
- Answer
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D
What processing step enhances the stability of pre-tRNAs and pre-rRNAs?
- methylation
- nucleotide modification
- cleavage
- splicing
- Answer
-
A
15.5: Ribosomes and Protein Synthesis
Review Questions
The RNA components of ribosomes are synthesized in the ________.
- cytoplasm
- nucleus
- nucleolus
- endoplasmic reticulum
- Answer
-
C
In any given species, there are at least how many types of aminoacyl tRNA synthetases?
- 20
- 40
- 100
- 200
- Answer
-
A
Free Response
Transcribe and translate the following DNA sequence (nontemplate strand): 5'-ATGGCCGGTTATTAAGCA-3'
- Answer
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The mRNA would be: 5'-AUGGCCGGUUAUUAAGCA-3'. The protein would be: MAGY. Even though there are six codons, the fifth codon corresponds to a stop, so the sixth codon would not be translated.
Explain how single nucleotide changes can have vastly different effects on protein function.
- Answer
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Nucleotide changes in the third position of codons may not change the amino acid and would have no effect on the protein. Other nucleotide changes that change important amino acids or create or delete start or stop codons would have severe effects on the amino acid sequence of the protein.


16.6: Equity Financing
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5. When and how do firms issue equity, and what are the costs?
Equity refers to the owners’ investment in the business. In corporations, the preferred and common stockholders are the owners. A firm obtains equity financing by selling new ownership shares (external financing), by retaining earnings (internal financing), or for small and growing, typically high-tech, companies, through venture capital (external financing).
Selling New Issues of Common Stock
Common stock is a security that represents an ownership interest in a corporation. A company’s first sale of stock to the public is called an initial public offering (IPO) . An IPO often enables existing stockholders, usually employees, family, and friends who bought the stock privately, to earn big profits on their investment. (Companies that are already public can issue and sell additional shares of common stock to raise equity funds.)
But going public has some drawbacks. For one thing, there is no guarantee an IPO will sell. It is also expensive. Big fees must be paid to investment bankers, brokers, attorneys, accountants, and printers. Once the company is public, it is closely watched by regulators, stockholders, and securities analysts. The firm must reveal such information as operating and financial data, product details, financing plans, and operating strategies. Providing this information is often costly.
Going public is the dream of many small company founders and early investors, who hope to recoup their investments and become instant millionaires. Google, which went public in 2004 at $85 a share and soared to $475 in early 2006 before settling back to trade in the high-300 range in August 2006. More than a decade later, in October 2017, Google continues to be a successful IPO, trading at more than $990 per share.
In recent years, the number of IPOs has dropped sharply, as start-ups think long and hard about going public, despite the promise of millions of dollars for investors and entrepreneurs. For example, in 2017, Blue Apron, a meal-kit delivery service, went public with an opening stock price of $10 per share. Several months later, the share price dropped more than 40 percent. Some analysts believe that Amazon’s possible entry into the meal-kit delivery sector has hurt Blue Apron’s value, as well as the company’s high marketing costs to attract and retain monthly subscribers. 8
Some companies choose to remain private. Cargill, SC Johnson, Mars, Publix Super Markets, and Bloomberg are among the largest U.S. private companies.
Dividends and Retained Earnings
Dividends are payments to stockholders from a corporation’s profits. Dividends can be paid in cash or in stock. Stock dividends are payments in the form of more stock. Stock dividends may replace or supplement cash dividends. After a stock dividend has been paid, more shares have a claim on the same company, so the value of each share often declines. A company does not have to pay dividends to stockholders. But if investors buy the stock expecting to get dividends and the firm does not pay them, the investors may sell their stocks.
At their quarterly meetings, the company’s board of directors (typically with the advice of its CFO) decides how much of the profits to distribute as dividends and how much to reinvest. A firm’s basic approach to paying dividends can greatly affect its share price. A stable history of dividend payments indicates good financial health. For example, cable giant Comcast has increased its dividend more than 20 percent over the past five years, giving shareholders a healthy return on their investment. 9
If a firm that has been making regular dividend payments cuts or skips a dividend, investors start thinking it has serious financial problems. The increased uncertainty often results in lower stock prices. Thus, most firms set dividends at a level they can keep paying. They start with a relatively low dividend payout ratio so that they can maintain a steady or slightly increasing dividend over time.
Retained earnings , profits that have been reinvested in the firm, have a big advantage over other sources of equity capital: They do not incur underwriting costs. Financial managers strive to balance dividends and retained earnings to maximize the value of the firm. Often the balance reflects the nature of the firm and its industry. Well-established and stable firms and those that expect only modest growth, such as public utilities, financial services companies, and large industrial corporations, typically pay out much of their earnings in dividends. For example, in the 2016 fiscal year, ExxonMobil paid dividends of $3.08 per share, Altria Group paid $2.64 per share, Apple paid $2.23 per share, and Costco paid $2.00 per share.
Most high-growth companies, such as those in technology-related fields, finance much of their growth through retained earnings and pay little or no dividends to stockholders. As they mature, many decide to begin paying dividends, as Apple decided to do in 2012, after 17 years of paying no annual dividends to shareholders. 10
Preferred Stock
Another form of equity is preferred stock . Unlike common stock, preferred stock usually has a dividend amount that is set at the time the stock is issued. These dividends must be paid before the company can pay any dividends to common stockholders. Also, if the firm goes bankrupt and sells its assets, preferred stockholders get their money back before common stockholders do.
Like debt, preferred stock increases the firm’s financial risk because it obligates the firm to make a fixed payment. But preferred stock is more flexible. The firm can miss a dividend payment without suffering the serious results of failing to pay back a debt.
Preferred stock is more expensive than debt financing, however, because preferred dividends are not tax-deductible. Also, because the claims of preferred stockholders on income and assets are second to those of debtholders, preferred stockholders require higher returns to compensate for the greater risk.
Venture Capital
Venture capital is another source of equity capital. It is most often used by small and growing firms that aren’t big enough to sell securities to the public. This type of financing is especially popular among high-tech companies that need large sums of money.
Venture capitalists invest in new businesses in return for part of the ownership, sometimes as much as 60 percent. They look for new businesses with high growth potential, and they expect a high investment return within 5 to 10 years. By getting in on the ground floor, venture capitalists buy stock at a very low price. They earn profits by selling the stock at a much higher price when the company goes public. Venture capitalists generally get a voice in management through seats on the board of directors. Getting venture capital is difficult, even though there are hundreds of private venture-capital firms in this country. Most venture capitalists finance only about 1 to 5 percent of the companies that apply. Venture-capital investors, many of whom experienced losses during recent years from their investments in failed dot-coms, are currently less willing to take risks on very early-stage companies with unproven technology. As a result, other sources of venture capital, including private foundations, states, and wealthy individuals (called angel investors ), are helping start-up firms find equity capital. These private investors are motivated by the potential to earn a high return on their investment.
CONCEPT CHECK
- Compare the advantages and disadvantages of debt and equity financing.
- Discuss the costs involved in issuing common stock.
- Briefly describe these sources of equity: retained earnings, preferred stock, venture capital.


3.1: Why It Matters
IDENTIFY AND COMPARE COMMON ROCK FORMING MINERALS, INTERPRET AND UNDERSTAND MINERAL STRUCTURES, MINERAL PROPERTIES
In this section we will learn about the rock cycle. Please watch this short video for an introduction:
As you can see, the rock cycle is never ending. The video explained how rocks change from one rock type to another, and—just as important—it showed the processes that cause those changes.
Learning the rock cycle and understanding the processes involved helps all of us. For example, you saw in the video how all rocks are eroded into fine particles. This is how soil forms, through the breakdown of rocks. We need soil to survive—imagine trying to grow vegetables without it. This is an immediate connection to the food chain. The rock cycle also gives scientists and engineers an idea on where energy sources (mainly fossil fuels, which are found only in sedimentary rock) and building materials such as marble or granite may be located. We will see throughout the course how this cycle plays into just about every aspect of geology.
Learning Outcomes
- Interpret and explain all processes of the rock cycle
- Differentiate between metamorphic, igneous, and sedimentary rock types
Ok, let's get started!
Contributors and Attributions
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Original content from Kimberly Schulte (Columbia Basin College) and supplemented by Lumen Learning . The content on this page is copyrighted under a Creative Commons Attribution 4.0 International license.


20.3: Nutrition and Chronic Musculoskeletal and Integumentary Illness
By the end of this section, you should be able to:
- 20.2.1 Discuss the impact of nutrition on musculoskeletal and integumentary illness.
Nutritional Requirements for Optimal Musculoskeletal and Integumentary Health
Diet is an important factor to consider for preserving muscle mass . Protein and amino acids support muscle synthesis and help maintain healthy muscle mass in all individuals. The nurse should teach the client with decreased muscle mass the importance of maintaining adequate protein intake. Additionally, various studies have shown that certain individuals experiencing low muscle mass due to malnutrition can benefit from oral nutritional supplements (Prado et al., 2022). An assessment by a health care provider will allow them to help a client decide which supplements are appropriate for their individualized needs.
One of the most important ways an individual of any age can maintain optimal musculoskeletal and integumentary health is through a healthy diet and exercise and by maintaining a healthy body weight and composition. In addition to monitoring a client’s weight, measuring body mass index (BMI) and waist-hip ratio (WHR) are examples of noninvasive tools used to screen clients for obesity. Not only do underweight and overweight individuals have a greater risk for musculoskeletal problems, but because adipose tissue is part of the integumentary system, weight is intimately tied to this body system.
Nutrition and Skin Integrity
As explained previously, the relationship between pressure injuries (also known as pressure ulcer, pressure injury, decubitus) and the aging process in the older adult is complex. Although aging results in thinner and more fragile skin, other variables can add to an older adult’s increased risk for skin breakdown and wounds. Some older adults live sedentary lifestyles that contribute not only to increased pressure on certain areas of the skin but also to deconditioning of the muscles. Older adults may have unintended weight loss. In addition, older adults can experience malnutrition for many reasons, leading to insufficient intake of macronutrients and micronutrients. Because nutrition and adequate hydration are essential for wound healing , malnutrition can in turn increase the risk for developing wounds and pressure injuries and may interfere with wound healing (Munoz, 2019).
Even small periods of malnutrition can cause delayed wound healing. Therefore, in addition to a healthy, balanced diet, health care providers usually recommend oral nutritional supplements with added protein and amino acids for clients with delayed wound healing due to malnutrition (Manley & Mitchell, 2022).
Nurses should encourage the use of a standardized nutritional risk assessment tool for older adults with wounds in their care practice setting. These tools, such as the Mini Nutritional Assessment (MNA), can help the nurse identify clients at risk for delayed wound healing and can help identify targeted areas of nutrition education for older adults with delayed wound healing (Fulton et al., 2016).
The MNA has been validated and is highly sensitive; it has demonstrated good reliability and accuracy in identifying older adults who are malnourished or at risk for malnutrition. It is typically administered by health care professionals, and it can be used in various health care settings, including hospitals, nursing homes, and community care settings. The assessment considers various factors that influence nutritional status, including dietary intake, mobility, weight loss, and psychological factors. The MNA questionnaire portion consists of questions that cover a range of topics, such as appetite, weight loss, mobility, and chronic diseases. The questions aim to gather information about the individual’s dietary habits, recent weight changes, and ability to perform daily activities. Additionally, the MNA includes anthropometric measurements such as BMI, calf circumference, and mid-arm circumference, which provide objective data on muscle and fat stores.
Based on the responses to the MNA questionnaire and the measurements taken, individuals are categorized into one of three groups:
- Well-nourished: Individuals who have good nutritional status and no apparent risk for malnutrition
- At risk for malnutrition: Individuals who show signs of poor nutritional status or have certain risk factors for malnutrition
- Malnourished: Individuals who are already malnourished or have severe nutritional deficiencies
The MNA can help health care professionals make informed decisions regarding nutritional interventions for clients, such as the need for dietary modifications, oral nutritional supplements, or referral to a dietitian for further assessment and management.
The MNA was developed more than two decades ago by the Nestlé Nutrition Institute. Nurses can use this tool in a variety of settings to identify clients at risk for malnutrition or delayed wound healing and to implement appropriate interventions. The short version of the assessment is available at this site , which includes a video on its use.
Read the following clinical scenario and then answer the questions that follow. This case study is a follow-up from Case Study Parts A, B, and C.
Time flies! Jose is now 74 years old and has a pressure injury. Read through the following summary of Jose’s visit to the wound clinic.
| Vital Signs | Nurse’s Note | |
|---|---|---|
| Temperature: | 98.6° F |
|
| Blood pressure: | 122/68 mm Hg | |
| Heart rate: | 80 beats/min | |
| Respiratory rate: | 14 breaths/min | |
| Pain: | 6/10 in right hip decubitus | |
| BMI: | 18.5 | |
| Calf circumference: | 29 cm |
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Taking prescribed oral nutritional supplements
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Repeating the MNA screening at regular intervals
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Switching from skim milk to 2% milk
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Eating less red meat
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Obese
-
Underweight
-
Overweight
-
Malnourished


5.7: Ethics, Corporate Culture, and Compliance
- Understand the differences between values-based ethics and compliance in organizations.
An organization’s culture is defined by the shared values and meanings its members hold in common and that are articulated and practiced by its leaders. Purpose, embodied in corporate culture, is embedded in and helps define organizations. Ed Schein, one of the most influential experts on culture, also defined organizational corporate culture as “a pattern of shared tacit assumptions learned or developed by a group as it solves its problems of external adaptation and internal integration that have worked well enough to be considered valid and, therefore, to be taught to new members as the correct way to perceive, think, and feel in relation to those problems" (Schein, 2017).
As Exhibit 5.6 illustrates, culture plays an important integrating role in organizations both externally and internally. Strategy, structure, people, and systems are all affected by an organization’s culture, which has been referred to as the “glue” that holds an organization together (Cameron & Quinn, 2011).
Leadership exerts a powerful influence on culture. Schein noted that “culture and leadership are two sides of the same coin and one cannot understand one without the other" (Schein, 2017). Culture is transmitted through:
- Values and styles that leaders espouse and practice
- Heroes and heroines that the company rewards and holds up as models
- Rites and symbols that organizations value
- The way that organizational executives and members communicate among themselves and with their stakeholders.
Heskett argued that culture “can account for 20-30% of the differential in corporate performance when compared with ‘culturally unremarkable’ competitors" (Coleman, 2013).
While subcultures develop in organizations, the larger organization’s culture influences these, especially with strong leaders and leadership teams who set the tone at the top and communicate expectations and performance standards throughout. Other factors that indicate and help create a strong ethical culture include the following, which are based on the reputable assessment firm Ethisphere’s experience (Coffin, 2017).
An organization models and communicates compliance standards through its values; employees are informed of and familiar with the assets and efforts of the compliance and ethics function.
- The culture sets “enduring and underlying assumptions and norms that determine how things are actually done in the organization” (Killingsworth, 2012).
- “Organizations can effectively identify specific locations, business units, job levels, and job functions that may lack a full understanding of available resources, feel unwanted pressure, or perhaps hold negative perceptions.”
- Companies and investors believe a company behaves and acts ethically.
- Employees are aware of senior leaders' conduct, values, and communications.
- Employees are engaged and committed, and organizations regularly survey employees to get a sense of their engagement.
- Employees feel “less pressure to compromise company standards to achieve company goals. And if they do observe misconduct, they are more likely to feel comfortable reporting it.”
- “Employees perceive the ethical priorities of their coworkers, the values of their organization and willingness to share opinions" (Coffin, 2017).
Compliance and Ethics
As the section above indicates, both values-based and compliance approaches are necessary for maintaining an ethical corporate culture. Ethics has been characterized as “doing the right thing” and as a motivational force influencing professionals’ values—resembling a “carrot” approach to professionals’ behaviors. Compliance is related to influencing behaviors to act according to the law or face consequences—referred to as a “stick” approach. Studies show that ethical and compliance approaches are interrelated and work best to motivate and sustain lawful and ethical behavior in organizations (Weller, 2017).
One law in particular set a new baseline of accountability for chief executive officers (CEOs) and chief financial officers (CFOs): the federal Sarbanes-Oxley Act of 2002, 2010. This law was the first following the Enron scandal and other corporate scandals that placed constraints and issued punitive measures on CEOs and CFOs who could be punished if they knowingly and willingly committed fraud and other crimes. Several new sections of that law also signaled a change in corporate leaders’ responsibilities and liabilities; for example, the law “[establishes] an independent public company accounting board to oversee audits of public companies; requires one member of the audit committee to be a finance expert; requires full disclosure to stockholders of complex financial transactions: requires CEOs and CFOs to certify in writing the validity of their companies’ financial statements. If they knowingly certify false statements, they can go to prison for 20 years and be fined $5 million; -Prohibits accounting firms from offering other services, like consulting, while also performing audits” (Federal Sentencing Guidelines, 2004). Other parts of this law further establish compliance regulations (PriceWaterhouseCoopers, 2003).
Because of the widespread corporate scandals discussed at the beginning of the chapter, the U.S. Congress implemented legal and compliance standards to curb and discourage illegal activities in corporations. While self-regulation will always play a major role in corporations’ “doing the right thing,” compliance has proven to be a necessary but not always sufficient element of corporate governance. Ethics continues to complement compliance, especially since the law cannot, does not, and will not cover every aspect of potentially harmful behaviors. Ethical dimensions and practices such as transparency, privacy, honesty, objectivity, integrity, carefulness, openness, respect for intellectual property, civility, confidentiality, accountability, responsible mentoring, and respect for colleagues are all necessary to motivate organizational behavior.
Ethical values become “actionable” in corporations when corporations first become aware of and then assume responsibility for the corporation’s duties toward its stakeholders and stockholders. Social responsibility as a concept originated in 1953 when Howard R. Bowen, known as the “father of corporate social responsibility” (CSR), referred to in a book to the “Social Responsibilities of the Businessman" (Carroll, 2008).
- In what ways do law and compliance complement ethics in organizations?
- How does stakeholder management differ from stockholder management?


6.2.1: Transition Metal Alkyl Complexes
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Learning Objectives
In this lecture you will learn the following
- Get a general prospective on the historical background of transition metal organometallic compounds with particular emphasis on metal alkyls.
- Know more about stable metal alkyls.
- Get introduced to transition metal agostic alkyls.
- Develop an understanding of reactions of relevance to metal alkyls like the reductive eliminations, oxidative additions and the halide eliminations.
Transition metal σ−bonded organometallic compounds like the metal alkyls, aryls and the hydrides derivatives are by for the most common organometallic species encountered in the world of chemistry. Yet, these compounds remained elusive till as late as the 1960s and the 1970s.
Historical background
Metal alkyls of the main group elements namely, Li, Mg, Zn, As and Al, have been known for a long time and which over the years have conveniently found applications in organic synthesis whereas development on similar scale and scope in case of the transition metal counterparts were missing till only recently. The origin of the organometallic compounds traces back to 1757, when Cadet prepared a foul smelling compound called cacodyl oxide from As 2 O 3 and CH 3 COOK, while working in a military pharmacy in Paris. Years later in 1840, R. W. Bunsen gave the formulation of cacodyl oxide as Me 2 As−O−AsMe 2 . The next known transition metal organometallic compound happens to be Et 2 Zn, which was prepared serendipitously in 1848 from the reaction of ethyl iodide (EtI) and Zn with the objective of generating free ethyl radical. Frankland further synthesized alkyl mercury halides like, CH 3 HgI, from the reaction of methyl iodide (CH 3 I) and Hg in sunlight. It is important to note that the dialkyl mercury, R 2 Hg, and the dialkyl zinc, R 2 Zn, have found applications as alkyl transfer reagents in the synthesis of numerous main group organometallic compounds.
Another notable development of the time was of the preparation of Et 4 Pb from ethyl iodide (EtI) and Na/Pb alloy by C. J. Lowig and M. E. Schweizer in 1852. They subsequently extended the same method for the preparation of the Et 3 Sb and Et 3 Bi compounds. In 1859, aluminumalkyliodides, R 2 AlI, were prepared by W. Hallwachs and A Schafarik from alkyl iodide (RI) and Al. The year 1863 saw the preparation of organochlorosilanes, RmSiCl 4−m , by C. Friedel and J. M. Crafts while the year 1866 saw the synthesis of halide-free alkyl magnesium compound, Et 2 Mg, by J. A. Wanklyn from the reaction of Et 2 Hg and Mg. In 1868, M. P. Schutzenberger reported the first metal−carbonyl complex in the form of [Pt(CO)Cl 2 ] 2 . In 1890, the first binary metal−carbonyl compound, Ni(CO) 4 was reported by L. Mond, who later founded the well−known chemical company called ICI (Imperial Chemical Industries). In 1909, W. J. Pope reported the first σ−organotransition metal compound in the form of (CH 3 ) 3 PtI. In 1917, the alkyllithium, RLi, compounds were prepared by W. Schlenk by transalkylation reactions. In 1922, T. Midgley and T. A. Boyd reported the utility of Et 4 Pb as an antiknock agent in gasoline. A. Job and A. Cassal prepared Cr(CO) 6 in 1927. In 1930, K. Ziegler showed the utility of organolithium compounds as alkylating agent while in the following year in 1931, W. Heiber prepared Fe(CO) 4 H 2 as the first transition metal−hydride complex. O. Roelen discovered the much renowned hydroformylation reaction in 1938, that went on to become a very successful industrial process worldwide.
The large scale production and the use of silicones were triggered by E. G. Rochow, when he reported the ‘direct synthesis’ from methyl chloride (CH 3 Cl) and Si using Cu catalyst at 300 °C in 1943. The landmark compound, ferrocene (C 5 H 5 ) 2 Fe, known as the first sandwich complex was obtained by P. Pauson and S. A. Miller in 1951. H. Gilman introduced the important utility of organocuprates when he prepared LiCu(CH 3 ) 2 , in 1952. In the subsequent year 1953, G. Wittig found a new method of synthesizing olefins from phosphonium ylides and carbonyl compounds that fetched him a Nobel prize in 1979. The year 1955 turned out to be a year of path breaking discoveries with E. O. Fischer reporting the rational synthesis of bis(benzene)chromium, (C 6 H 6 ) 2 Cr while K. Ziegler and G. Natta announcing the ground breaking polyolefin polymerization process that subsequently gave them the Nobel prizes, E. O. Fischer sharing with G. Wilkinson in 1973 while K. Ziegler and G. Natta shared the same in 1963. In 1956, H. C. Brown reported hydroboration for which he too received the Nobel prize in 1979. In 1963, L. Vaska reported the famous Vaska’s complex, trans −(PPh 3 ) 2 Ir(CO)Cl, that reversibly binds to molecular oxygen. In 1964, E. O. Fischer reported the first carbene complex, (CO) 5 WC(OMe)Me. In 1965, G. Wilkinson and R. S. Coffey reported the Wilkinson catalyst, (PPh 3 ) 3 RhCl, for the hydrogenation of alkenes. In 1973, E. O. Fischer synthesized the first carbyne complex, I(CO) 4 Cr(CR).
After the early 1970s, there were tremendous outburst in activity, in the area of transition metal organometallic chemistry leading to phenomenal developments having far-reaching consequences in various branches of the main stream and interfacial chemistry. Several Nobel prizes that have been awarded to the area in recent times fully recognized the significance of these efforts with Y. Chauvin, R. R. Schrock, and R. H. Grubbs winning it in 2005 for olefin metathesis and Akira Suzuki, Richard F Heck and E. Negishi receiving the same for the Pd catalyzed C−C cross-coupling reactions in organic synthesis in 2010.
Metal alkyls
In day to day organic synthesis, particularly from the application point of view, the metal alkyls are often perceived as a source of stabilized carbanions for reactions with various electrophiles. The extent of stabilization of alkyl carbanions in metal alkyl complexes depend upon the nature of the metal cations. For example, the alkyls of electropositive metals like that of Group 1 and 2, Al and Zn are regarded as polar organometallics as the alkyl carbanions remain weakly stabilized while retaining strong nucleophilic and basic character of a free anion. These polar alkyls are extremely air and moisture sensitive as in their presence they often get hydrolyzed and oxidized readily. Similar high reactivity was also observed in case of the early transition metal organometallic compounds particularly of Ti and Zr. On the contrary the late transition metal organometallic compounds are much less reactive and stable. For example, the Hg−C bond of (Me−Hg) + cation is indefinitely stable in aqueous H 2 SO 4 solution in air. Thus, on moving from extremely ionic Na alkyls to highly polar covalent Li and Mg alkyls and to essentially covalent late−transition metal alkyls, a steady decrease in reactivity is observed. This trend can be correlated to the stability of alkyl carbanions that also depended on the nature of hybridization of the carbon center, with sp 3 hybridized carbanions being the least stable and hence most reactive, followed by the sp 2 carbanions being moderately stable while the sp carbanions being the least reactive and most stable. The trend also correlates well with the respective p K a values observed for CH 4 (p K a = ~50), C 6 H 6 (p K a = ~43) and RC≡CH (p K a = ~25).
Stable alkyls
As has been mentioned earlier, that the β−elimination is a crucial destabilizing influence on the transition metal organometallic complexes. Hence, inhibition of this decomposition pathway leads to increased stabilities of organometallic compounds. Thus, many stable alkyl transition metal complexes do not possesses β−hydrogens like, W(Me) 6 and Ti(CH 2 Ph) 4 . In some cases despite the presence of the β−hydrogens the organometallic complexes are stable as the β−hydrogens are deposed away from the metal center like in, Cr(CHMe 2 ) 4 , and Cr(CMe 3 ) 4 . In this category of stable transition metal organometallic compounds also falls the ones that contain β−hydrogens but cannot β−eliminate owing to the formation of a olefinic bond at a bridgehead, which is unfavorable, like in Ti(6−norbornyl) 4 and Cr(1−adamantyl) 4 . Lastly, some 18 VE metal complexes are stable, again despite having β−hydrogens, for reasons of being electronically as well as coordinatively saturated at the metal center owing to attaining the stable 18 electron configuration.
Agostic alkyls
Agostic alkyls are extremely rare but very interesting species that represents a frozen point in a β−elimination pathway that have fallen short of the completion of the decomposition reaction. Thus, these agostic alkyl complexes can be viewed as snap shots of a β−elimination trajectory thereby providing valuable mechanistic understanding of the decomposition reaction. The agostic interaction has characteristic signatures in various spectroscopic techniques as observed from the decreasing J C− H coupling constant values in the 1 H NMR and the 13 C NMR spectra and the lowering of the ν C − H stretching frequencies in the IR spectroscopy. The agostic alkyl complexes can be definitively proven by X−ray diffraction or neutron diffraction studies. The agostic alkyls thus have activated C−H bonds which are of interest for their utility in chemical catalysis. Quite interestingly, many d 0 Ti agostic alkyl complexes do not β−eliminate primarily for the metal center being too electron deficient to donate electron to the σ* C−H orbital as required for the subsequent β−elimination process.
Reductive elimination
Reductive elimination represents a major decomposition pathway of the metal alkyls. Opposite of oxidative addition, the reductive elimination is accompanied by the decrease in the oxidation state and the valence electron count of the metal by two units. The metal alkyl complexes may thus reductively eliminate with an adjacent hydrogen atom to yield an alkane, (R−H) or undergo the same with an adjacent alkyl group to give an even larger alkane (R−R) as shown below.
\[\ce{L_{n}MRH -> R-H + L_{n}M} \nonumber \]
\[\ce{L_{n}MR2 -> R-R + L_{n}M} \nonumber \]
The reductive elimination is often facilitated by an electron deficient metal center and by sterically demanding ligand systems. Often d 8 metals like Ni(II), Pd(II), and Au(III) and d 6 metals in high oxidation state like, Pt(IV), Pd(IV), Ir(III), and Rh(III) exhibit reductive elimination.
Oxidative addition
Unlike the reductive elimination that represents a decomposition pathway of metal alkyls, the oxidative addition reaction represents a useful method for the formation of the metal alkyl complexes. The oxidative addition thus leads to increase in valence electron count and the oxidation state of the metal center by two units. The oxidative addition reactions are often facilitated by low valent electron rich metal centers and by less sterically demanding ligands.
Halide elimination
β−halide elimination is observed for the early transition metals and the f −block elements resulting in the formation of stable alkyl halides. The phenomenon is mostly seen in case of the metal fluorides and arise owing to the very high alkyl−fluoride bond strengths that favor the halide elimination.
Problems
1. Who elucidated the structure of cacodyl oxide?
Ans: R. W. Bunsen in 1840
2. Give the example of the first olefin bound transition metal complex?
Ans: Zeise's salt, Na[PtCl 3 (C 2 H 4 )]
3. Who discovered olefin polymerization?
Ans: K. Ziegler and G. Natta
4. What kind of metal center promotes oxidative addition reactions?
Ans: Electron rich
5. The 18 VE complex would favor/disfavor oxidative addition reactions?
Ans: Disfavor
Self Assessment test
1. O. Roelen discovered which famous reaction?
Ans: Hydroformylation
2. What is the first binary metal−carbonyl complex?
Ans: Ni(CO) 4
3. Who discovered the hydroboration reaction?
Ans: H. C. Brown
4. Reductive elimination reaction is favored by what kind of ligands?
Ans: Sterically demanding
5. β−halide elimination is mainly observed for what type of metal halide complexes?
Ans: Metal fluorides
Summary
A broader outlook on metal alkyls is obtained from the study of its historical background thus dispelling many myths about these compounds like them being inherently unstable. It also establishes newer founding principles like these compounds indeed being thermodynamically stable under certain experimental conditions and thus facilitating further attempts to take up the synthesis of these compounds. Another important class of transition metal organometallic compounds are the agostic alkyls, which can be viewed as the ones that have proceeded along but have fallen short of the final sequence of the β−elimination step. While oxidative addition reaction remains a key method for synthesizing metal alkyls, the complementary reaction, i.e , the reductive elimination, represents a decomposition reaction of these compounds. β−halide elimination reactions are observed for early transition metal elements and f −block elements.


43.4A: Male Hormones
- Explain the function of male hormones in reproduction
Male Hormones
Puberty is a period of several years in which rapid physical growth and psychological changes occur, culminating in sexual maturity. The average onset of puberty is age 11 or 12 for boys. Some of the most significant parts of pubertal development involve distinctive physiological changes in individuals’ height, weight, body composition, and circulatory and respiratory systems. These changes are largely influenced by hormonal activity. Hormones play an organizational role, priming the body to behave in a certain way once puberty begins, and an activational role, referring to changes in hormones during adolescence that trigger behavioral and physical changes.
At the onset of puberty, the hypothalamus begins secreting high pulses of GnRH, or gonadotropin-releasing hormone. In response, the pituitary gland releases follicle stimulating hormone (FSH) and luteinizing hormone (LH) into the male system for the first time. FSH enters the testes, stimulating the Sertoli cells, which help to nourish the sperm cells that the testes produce, to begin facilitating spermatogenesis. LH also enters the testes, stimulating the interstitial cells, called Leydig cells, to make and release testosterone into the testes and the blood.
Testosterone, the hormone responsible for the secondary sexual characteristics that develop in the male during adolescence, stimulates spermatogenesis, or the process of sperm production in the testes. Secondary sex characteristics include a deepening of the voice, the growth of facial, axillary, and pubic hair, and the beginnings of the sex drive.
A negative feedback system occurs in the male with rising levels of testosterone acting on the hypothalamus and anterior pituitary to inhibit the release of GnRH, FSH, and LH. The Sertoli cells produce the hormone inhibin, which is released into the blood when the sperm count is too high. This inhibits the release of GnRH and FSH, which will cause spermatogenesis to slow down. If the sperm count reaches 20 million/ml, the Sertoli cells cease the release of inhibin, allowing the sperm count to increase.
Key Points
- The onset of puberty is signaled by high pulses of GnRH secreted by the hypothalamus; this in turn signals the release of FSH and LH from the pituitary gland.
- FSH causes the Sertoli cells of the testes (which help nurse developing sperm cells) to begin the process of spermatogenesis in the testes.
- LH triggers the production of testosterone from the Leydig cells of the testis; testosterone causes the development of secondary sex characteristics in the male.
- As spermatogenesis and testosterone production increase, the Sertoli cells produce inhibin, which, together with rising levels of testosterone, inhibit the release of FSH and LH from the pituitary gland.
Key Terms
- puberty : the age at which a person is first capable of sexual reproduction
- Sertoli cell : a kind of sustentacular cell which serves as a “nurse” cell of the testes and which is part of a seminiferous tubule
- Leydig cell : one of the interstitial cells, located next to the seminiferous tubules inside the testicle, that produce testosterone
- follicle stimulating hormone : a gonadotropic glycoprotein hormone, secreted in the anterior pituitary, that stimulates the growth of ovarian follicles in female mammals, and induces spermatogenesis in male mammals
- luteinizing hormone : a hormone, produced by part of the pituitary gland, that stimulates ovulation and the development of the corpus luteum in female mammals, and the production of androgens by male mammals
- inhibin : a peptide hormone, secreted by the gonads, which inhibits the secretion of follicle-stimulating hormone
- testosterone : steroid hormone produced primarily in the testes of the male; it is responsible for the development of secondary sex characteristics in the male


12.7: Intercultural Communication References
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“10 Privileges I Have Complained About.” BuzzFeed . N.p., n.d. Web. 7 Dec. 2014.
Alley-Young, Gordon. “Articulating Identity: Refining Postcolonial And Whiteness Perspectives On Race Within Communication Studies.” Review Of Communication 8.3 (2008): 307-321. Communication & Mass Media Complete. Web. 13 Oct. 2014.
Asante, Molefi Kete. Afrocentricity . Trenton. NJ: Africa World Press, 1988. Print.
Asante, Molefi Kete. T he Afrocentric Idea (rev. Ed.). Philadelphia: Temple UP (1998): n. pag. Print.
Buchanan, Larry. “What Happened in Ferguson?” The New York Times 13 Aug. 2014. NYTimes.com. Web.
Brummett, Barry. Rhetoric in Popular Culture . Sage Publications, 2014. Print.
Geert, Hofstede, and Hofstede Gert Jan. Cultures and Organizations: Software of the Mind . McGraw-Hill, New York (1991): n. pag. Print.
Giles, Howard and Kimberly A. Noels. “Communication Accommodation in Intercultural Encounters.” Readings in Intercultural Communication . Eds. Judith N. and Thomas K. Nakayama and Lisa A. Flores Martin. 2nd ed. Boston: McGraw Hill, 2002.
Gudykunst, William B., Stella Ting-Toomey, and Elizabeth Chua. Culture and Interpersonal Communication . Sage Publications, Inc, 1988. Google Scholar. Web. 15 Oct. 2014
Hall, Edward T. Beyond Culture . Garden City: Doubleday, 1976.
Hardiman, Rita. “White Racial Identity Development in the United States.” Race, ethnicity and self: Identity in multicultural perspective (1994): 117–140. Print.
Hymes, D. “Models of the Interaction of Language and Social Life.” Directions Is Sociolinguistics: The Ethnography of Communication . Ed. J. and D. Hymes Gumperz. Cambridge: Cambridge University Press, 1972. 35-71.
Hofstede, Geert. Cultures and Organizations: Software of the Mind . London; New York: McGraw-Hill, 1991.
Langston, D. “Tired of Playing Monopoly?” Race, Class, and Gender: An Anthology . Ed. M.L. Anderson and P.H. Collins. Belmont: Wadsworth, 1995. 100-09.
Levine, Bruce E. “How America’s Obsession With Money Deadens Us.” Alternet. N.p., 18 Mar. 2012. Web. 16 Nov. 2014.
Matsuda, Mari J., C. R. Lawrence, R. Delgado, and K. W. Crenshaw. Words That Wound: Critical Race Theory, Assaultive Speech, and the First Amendment . Boulder, CO: Westview, 1993. Print.
Martin, Judith N., and Olga Idriss Davis. “Conceptual Foundations for Teaching about Whiteness in Intercultural Communication Courses.” Communication Education 50.4 (2001): 298–313.Print.
Martin, Judith, and Thomas Nakayama. Intercultural Communication in Contexts . 5 edition. New York: McGraw-Hill Humanities/Social Sciences/Languages, 2009. Print.
McIntosh, Peggy. White Privilege and Male Privilege: A Personal Account of Coming to See Correspondences Through Work in Women’s Studies . Wellesley, MA: Wellesley College, Center for Research on Women, 1988. Print.
McIntosh, Peggy. “Reflections and Future Directions for Privilege Studies.” Journal of Social Issues 68.1 (2012): 194–206. Wiley Online Library. Web.
O’Neil, Dennis. “Ethnicity and Race: World Diversity Patterns.” Ethnicity and Race: World Diversity Patterns . 6 July 2006. Web. 3 Dec. 2014. <anthro.palomar.edu/ethnicity/ethnic_5.htm>.
Orbe, Mark P., and Tina M. Harris. Interracial Communication: Theory Into Practice . 3rd ed. Sage, 2012. Print.
Philipsen, Gerry, and T. Albrecht. “A Theory of Speech Codes.” Developing communication theories 6 (1997): n. pag. Google Scholar. Web.
Pyle, Nathan. “10 Privileges I Have Complained About.” BuzzFeed . N.p., n.d. Web
Phinney, Jean S. “A Three-Stage Model of Ethnic Identity Development in Adolescence.” Ethnic identity: Formation and transmission among Hispanics and other minorities 61 (1993): 79. Print.
Ponterotto, Joseph G., Shawn O. Utsey, and Paul B. Pedersen. Preventing Prejudice: A Guide for Counselors, Educators, and Parents . 2nd edition. Thousand Oaks, Calif: SAGE Publications, Inc, 2006. Print.
Poston, W. S. Carlos. “The Biracial Identity Development Model: A Needed Addition.” Journal of Counseling & Development , 69.2 (1990): 152-155.
“RACE – Are We So Different?” A Project of the American Anthropological Association . American Anthropological Association, n.d. Web. <www.understandingrace.org/home.html>.
Remar, P. “Should College and Universities Prohibit ‘Hate Speech’ on Campus?” Paper presented at the annual meeting of Speech Communication Association. Atlanta, GA, 1991.
Smith, David J., and Shelagh Armstrong. If the World Were a Village: A Book about the World’s People . 2nd ed. Toronto: Kids Can, 2011. Print.
Valdiva, Angharad N. “Big Hair and Bigger Hoops: Rosie Perez Goes to Hollywood.” Readings in Cultural Contexts . Eds. Judith N. Martin, Thomas K. Nakayama, and Lisa A. Flores. Mountain View: Mayfield, 1998.
Wasserman, Todd. “Digital Nomads Travel the World While You Rot in Your Office.” Mashable . N.p., 9 Nov. 2014. Web. 12 Nov. 2014.
Wingfield-Hayes, Rupert “China’s Taste for the Exotic.” BBC 29 June 2002. bbc.co.uk. Web.
Wood, Victoria. “Victoria Wood Political Correctness Gone Mad Song.” YouTube. YouTube, 11 Sept. 2010. Web. 29 Oct. 2014.
Contributions and Affiliations
- Survey of Communication Study. Authored by : Scott T Paynton and Linda K Hahn. Provided by : Humboldt State University. Located at : https://en.wikibooks.org/wiki/Survey_of_Communication_Study . License : CC BY-SA: Attribution-ShareAlike


6.2: Reaction Concepts
Overarching Concepts
Reaction types are significant to all fields of chemistry because they are what characterize any transformation from starting materials to products. In the pantheon of reactions, we tend to focus on functional group creation and atom transformation, both of which can be accomplished through the menu of reaction types shown below:
- Rearrangement (RAR)
- Addition
- Substitution
- Elimination
- Pericyclic reaction
- Ox/Red
- Reaction design
- Atom economy
The above six (6) general reaction categories simplify the panoply of reactivity paradigms in the discipline of chemistry. We can nearly list every pertinent reaction within one or more of the listings shown. Indeed, even acid/base chemistry can fall under Addition or Elimination reactions based on their precise reactivity patterns. We will delve deeply into each type in the following sections.
Rearrangements (RARs)
A rearrangement reaction covers a broad swath of chemistry which is principally characterized by the rearrangement of the skeletal configuration of a molecular system to yield a structural isomer (a swapped-out form of the original structure while retaining the original atoms). Oftentimes, a substituent moves from one backbone atom to another backbone atom. In the classical organic chemistry example shown below, we witness the Wagner-Meerwein RAR.
A rearrangement is not exactly well depicted by discrete electron transfers shown by curly arrows. The actual mechanism of alkyl groups moving in Figure \(\PageIndex{1}\) involves a fluid transfer of the alkyl group along a bond that is not described by simple ionic bond-breaking and reformation. Explanation by orbital interactions provides a better approximation although it is possible to draw the curved arrows for a sequence of discrete electron transfers to give the same result as a RAR reaction.
There are other types of RARs besides the chemically induced one shown above: we can have thermal or photo-induced as well. In these latter cases, heat or light can act as the triggers to actuate the transformation.
Thermal RARs
The isomerization of unsubstituted azulene to naphthalene was the first reported and hence most studied thermal transformation for an aromatic hydrocarbon. Many mechanisms have been suggested, yet not a one has been unequivocally confirmed.
Five mechanisms were proposed: reversible ring-closure, shown above, a norcaradiene- vinylidene, diradical, methylene walk, and a spiran mechanism. The reversible ring- closure mechanism is inaccurate despite its overall scientific appeal and evidence, and as such, multiple reaction pathways were deemed occurring simultaneously. This idea was widely accepted. It was thought that at high temperatures one mechanism would be energetically favored although energetic studies displayed similar activation energies for all mechanisms [1].
Four mechanisms for thermal isomerizations are warranted: dyotropic, diradical, and two benzene ring contractions. A 1,2-carbon shift to a carbene preceding a 1,2-hydrogen shift, and a 1-2- hydrogen shift to a carbene followed by a 1,2-carbon shift. The dyotropic mechanism shows the 1,2-shift displayed in Figure \(\PageIndex{2}\) .
Photoinduced RARs
The mechanisms of organic photochemical reactions are a treasure trove for photochemists and physicists because they provide tremendous insight into fundamental electronic behavior as a function of energy-matter interactions. The absorption of ultraviolet light by organics may lead to a number of reactions. Over the last century, an immense quantity of photochemical reactions have become unearthed; it has been found that reactions that are unlikely in ground-states are accessible in electronic excited-state configurations. One of the earliest photochemical studies was on the natural product santonin. Ciamician (1857-1922) observed that under sunlight exposure, santonin gave several photoproducts. The structure of santonin (molecule on left in Figure 6-3) was first described by Clemo and Hayworth in 1929 whose initial photoproduct is lumisantonin. As depicted, the photoreaction involves a C-3 carbonyl group movement to C-2, the C-4 methyl has moved to C-1, and the C-10 carbon has been inverted.
This reaction is named after the German chemist Ernst Otto Beckmann (1853–1923). It is representative of an acid-catalyzed rearrangement of an oxime to an amide (when the oximes are cyclic, they yield “lactams”).
Caprolactam, in this example, is a very important chemical because it is the feedstock in the production of Nylon 6, a material used extensively in the manufacture of textiles, clothes, carpets, cushions, bulletproof vests, etc. The reaction includes acetic acid, hydrochloric acid, sulfuric acid, and acetic anhydride, to catalyze the rearrangement. Sulfuric acid is the most commonly used acid for commercial lactam production because it forms ammonium sulfate (a common agricultural fertilizer) as a by-product when neutralized with ammonia.
In general, rearrangements tend to have no waste of atoms because they are a type of isomerization. They are hence very atom economical and hence very efficient modes of chemical transformations. At this point, we will delve into a series of rearrangements to further illustrate the point.
Addition Reactions
This type of reaction occurs when in general two molecules covalently bind to form a larger one referred to as the adduct. These reactions are limited to chemical compounds that have multiple bonds, such as molecules with carbon–carbon double bonds (alkenes), triple bonds (alkynes) hetero double bonds like carbonyl (C=O) groups, or imine (C=N) groups. An addition reaction is typically the reverse of an elimination reaction. For example, the hydration of an alkene to an alcohol is the reverse of dehydration which leads to an oxidative product (alkene). Electrophilic and nucleophilic additions are the main types of polar addition. The non-polar additions can be free radical and cycloaddition.
In general, addition reactions are very common because they are simple, very powerful, robust, and preserve/conserve atom economy during the reaction sequence (think of the mathematical operation of addition – all numbers sum!). Thus, in general, no additional by-products are generated allowing for a clean and straight forward reaction scheme that in the final analysis may require little to no purification steps.
Substitution Reactions
These types of reactions are also known as single displacement reaction or single substitution reaction). One functional group is replaced by a more reactive functional group or else it would not happen (the reverse would be faster or more thermodynamically stable). Substitution reactions are classified either electrophilic or nucleophilic depending upon the reagents. A good example of a substitution reaction is halogenation. When chlorine gas (Cl-Cl) is irradiated with the appropriate light energy, several of the molecules photolyze into two chlorine radicals (Cl·) whose electrons are very nucleophilic. In Figure 6-6, one of radicals can rupture (homolytically) a C-H bond through abstraction of one of the equivalent protons on methane to form electrically neutral H-Cl. The other radical reforms a covalent bond with the CH 3 . to form CH 3 Cl.
Elimination Reactions
An elimination reaction typically involves the removal of two substituents a substrate in either a one or two-step mechanism. The one-step mechanism is the E2 reaction , and the two-step mechanism is the E1 reaction . The numbering scheme relates to the kinetics of the reaction, i.e., bimolecular and unimolecular, respectively.
Elimination reactions are important because they are among a very few set of useful reactions that generate unsaturation within organic molecules. They are the opposite of addition reactions and involve homolytic or heterolytic dissociation of molecular groups on adjacent (vicinal) atoms leading to increased bond order on these vicinal atoms.
For example,RCH 2 CH 2 OH → R-CH=CH 2 +H 2 O.This latter reaction requires the expulsion of a water to lead to one degree of unsaturation. The presence of a leaving group is a pre-requisite for these types of reactions.
In Figure \(\PageIndex{8}\), the opportunity to retain a hydrogen on the final structure is an unusual mechanistic phenomenon. The conversion relies on a strict orbitally conserved concerted mechanism in which the degree of unsaturation (terminal vinyl group) is generated in tandem with the abstraction of the proton by the lactonic ring oxygen. Such a sigmatropic shift would be over 3 atoms (hence, an unusual 1,3-hydride shift).
Pericyclic Reactions
A pericyclic reaction (Figure \(\PageIndex{9}\) ) is a reaction in which the transition state of the molecule has a cyclic geometry and progresses in a concerted manner. They are typically rearrangement reactions. The major classes of pericyclic reactions are electrocyclic, cycloaddition, sigmatropic, group transfer, cheletropic, and dyotropic, all of which are considered to be equilibrium processes.
These types of reactions are governed by Frontier Molecular Orbital (FMO) Theory. Frontier molecular orbitals for a molecule are so called because the orbitals are the “frontier” or vanguard (leaders) of electron occupation. These are known classically as the highest-energy occupied (HOMO) and lowest-energy unoccupied (LUMO) molecular orbitals. The HOMO is characterized by nucleophilic or electron donation, whereas the LUMO is the opposite. Chemical reactions and resonance are very successfully described by the overlap between a filled HOMO and an empty LUMO.
Acidity and basicity are terms used in FMO Theory very broadly. Acidity refers to a ligand, metal center, or orbital ability to accept electron density (from electron sources that include Brønsted bases). Basicity refers to a ligand, metal center, or orbital ability to donate electrons (to electron sinks that include Brønsted acids). The theory distinguishes among σ-acids, σ-bases, π-acids, and π-bases. The first two, σ-X, accept or donate electrons in a σ manner, aligned head on with another orbital, whereas the latter two, π-X, accept or donate electrons in a π manner, aligned side by side with another orbital.
A pericyclic reaction typically is unimolecular and zero order with respect to kinetics. As shown below, the bicyclic on the left is highly strained because of the 1,2 bridging and undergoes an electrocyclic RAR to relieve the steric stress associated with the heterocyclic cyclopropanoid moiety.
Diels-Alder
This is a [4+2] cycloaddition as already mentioned that occurs between a conjugated diene and a substituted alkene known as a dienophile to form a substituted cyclohexene. It was first described by Otto Diels and Kurt Adler in 1928 that lead to the Nobel Prize in Chemistry in 1950. It is a reliable method for forming 6- membered systems with good regio- and stereochemical control. The concept has been applied to other π-systems to provide the corresponding heterocycles (hetero-Diels–Alder reaction).
1,3-Dipolar Cycloaddition
This reaction occurs between a 1,3-dipole and a dipolarophile to form a five-membered ring (Figure \(\PageIndex{10}\) ). The reaction is sometimes referred to as the Huisgen cycloaddition which specifically describes the 1,3-dipolar cycloaddition between an organic azide and an alkyne to generate 1,2,3-triazole. Currently, this reaction is an important route to the region- and stereospecific synthesis of fivemembered heterocycles.
Cope Rearrangement (RAR)
The Cope RAR is an extensively studied [3,3]-sigmatropic RAR of 1,5-dienes developed by Arthur Cope. For example, 3-methyl-1,5-hexadiene heated to 300 °C yields 1,5- heptadiene (see Figure \(\PageIndex{11}\) ).
Oxidation/Reduction Reactions
The term “redox”, short for red uction– ox idation reaction, is used to describe the complete set of chemical reactions occurring for electron transfers leading to changes in oxidation states. Redox reactions require a reduction and complementary oxidation processes. The chemical species (reductant) where the electron is removed is oxidized, while the counter species (oxidant) to where it is added is reduced:
- Oxidation is the loss of electrons or increase in oxidation state;
- Reduction is the gain of electrons or a decrease in oxidation state.
As an example, in an electrolytic cell (shown in Figure \(\PageIndex{12}\) ), a complete redox (cycle) is shown.
In the example, zinc is being oxidized from Zn 0 → Zn +2 which is a net loss of two electrons per atom. The oxidized zinc solubilizes in the anodic solution and proceeds to pull over an anion from the cathodic solution through the electromotive force of the two electrons that it lost. In other words, the zinc cation is balanced by the anions (likely two chloride anions) in the cathodic solution. Simultaneously, copper sulfate cations (cupric cations) are reduced by the net influx of the two electrons. A redox reaction can occur relatively slowly, for example, in the case of rust, or more rapidly, as in fires.


41.3.35: Chapter 36
Case Study
1.
c.
Smoking is the most important because an estrogen-containing contraceptive can increase the likelihood of developing thrombophlebitis or thromboembolism.
2.
d.
The copper IUD is the longest-lasting contraceptive device and does not contain hormones. Because Susan is slightly overweight, has a smoking history, and has migraine headaches, any hormonal contraceptive may cause serious side effects.
Review Questions
1.
a.
Migraine headaches are a concern with contraceptive medications that contain progestins because they may exacerbate the headaches.
2.
b.
Oxytocin’s effect on the kidneys can cause water intoxication and dilutional hyponatremia, which are considered significant side effects. Signs and symptoms of hyponatremia are related to the central nervous system (CNS) and musculoskeletal system.
3.
d.
Nitroglycerin is contraindicated when a client is using drugs for ED. The combination can cause significant hypotension and possible cardiac arrest.
4.
a.
Prepubescent clients on testosterone therapy may develop early closure of epiphyseal growth plates and stunted growth. Testosterone therapy may need to be decreased or stopped.
5.
a.
MgSO
4
can cause serious life-threatening cardiac rhythm changes and circulatory collapse. Therefore, continuous cardiac monitoring is the most important order to implement.
6.
c.
Given the context of a high school football player with these signs and symptoms, the nurse should recognize that the student may be misusing steroids. This question can help the nurse further assess the situation.
7.
d.
Invasive dental procedures should not be planned during bisphosphonate therapy because of the high risk of developing bisphosphonate-induced osteonecrosis of the jaws (BIONJ).
8.
a.
Impaired liver function is a serious side effect of antiandrogen medications. Clients on bicalutamide have developed liver failure and died. Liver function must be monitored closely.
9.
b.
Bone density testing should be scheduled routinely to determine the effectiveness of the drug therapy.
10.
a.
In this case, the anabolic steroid would be used to improve health status, indicated by increased hemoglobin.


3.2: Exercise- Preprocessing and Averaging the Data from 10 Participants
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Before you start this exercise, quit from EEGLAB if it’s already running and then restart it so that you’re starting fresh. You might even want to restart Matlab. Set Chapter_3 (the folder with the data you downloaded for this chapter) to be Matlab’s current folder.
For this chapter, you’ll need averaged ERPs from 10 participants. You have three options for obtaining these ERPsets:
You can go through all the steps from Chapter 2 for each participant using the EEGLAB/ERPLAB GUI. The Chapter_3 folder contains a folder for each participant containing the raw EEG data, just like the data you processed in Chapter 2. This will take quite a bit of time, but you’ll really learn the preprocessing steps well by repeating them for each participant.
You can run the script named preprocess_and_average.m (which is in the Chapter_3 folder). It will run all the processing steps automatically and create the ERPset for each participant. The script file contains instructions for running it. The advantage of this approach is that you’ll get more comfortable running Matlab scripts (which will become increasingly useful as you progress through the book). If you’d like, you can process some or all of the participants manually first and then run this script. When you’re processing your own data, this is the right approach: You first process the data manually to make sure everything is OK, and then you run a script to reprocess the data to avoid any errors in the manual processing.
There is a subfolder named Pre-made_ERPsets inside the Chapter_3 folder that contains—you guessed it!—a pre-made ERPset for each participant. You can just move those ERPsets into the single-participant folders inside the Chapter_3 folder. This is the quick-and-easy approach, but you won’t learn as much.
No matter which way you do it, make sure that you end up with an ERPset file named N _N400.erp inside folder N for each participant (where N is the participant number). Then, load all 10 of these ERPsets into EEGLAB/ERPLAB (either with the script or using EEGLAB > ERPLAB > Load existing ERPset ). The ERPsets menu should now look like Screenshot 3.1.


34.3: Osmotic Diuretics
By the end of this section, you should be able to:
- 34.3.1 Identify the characteristics of osmotic diuretic drugs used for fluid volume excess and renal system disorders.
- 34.3.2 Explain the indications, actions, adverse reactions, and interactions of osmotic diuretic drugs used for fluid volume excess and renal system disorders.
- 34.3.3 Describe nursing implications of osmotic diuretic drugs used for fluid volume excess and renal system disorders.
- 34.3.4 Explain the client education related to osmotic diuretic drugs used for fluid volume excess and renal system disorders.
Osmotic diuretics decrease sodium and water reabsorption in the proximal tubule and the loop of Henle, increasing water loss. Mannitol, the primary osmotic diuretic, is typically used to treat increased intracranial and intraocular pressure.
Introduction and Use
Mannitol is a large sugar molecule that is readily filtered by the glomeruli and is not reabsorbed by the tubules. The resulting osmotic force increases the loss of sodium and water. Although mannitol is also approved to promote diuresis for acute renal failure and for excretion of toxic substances, it is used most commonly to treat increased intracranial pressure and increased intraocular pressure (Tenny et al., 2022). Mannitol reduces intracranial and intraocular pressures by moving water from the cells into the circulation. In the brain, mannitol creates an osmotic gradient that draws water across the blood–brain barrier. In the eye, mannitol draws water from the vitreous humor into the circulation, which decreases the pressure on the retina. Mannitol therapy requires close monitoring because of the risks for fluid volume excess, electrolyte imbalances, and adverse renal and neurologic effects of increased osmotic pressure.
Hypertonic saline solutions may be used in place of mannitol therapy because the saline solution does not cause hypovolemia in critically ill clients who may already be hypovolemic, hypotensive, or actively bleeding. There is some evidence that hypertonic saline solutions also improve cerebral perfusion and cellular oxygenation (Shi et al., 2020). In addition, in contrast to mannitol, the saline solution can be infused temporarily through a peripheral vein until central venous access is available, and it does not require special reconstitution or delivery systems. Moreover, the therapies are associated with similar clinical outcomes.
Adverse Effects and Contraindications
Mannitol, like other diuretics, can cause electrolyte abnormalities and dehydration. It can cause heart failure secondary to the rapid fluid shift of water into the intravascular space. Administration of the drug has also been associated with the development of AKI in clients with normal renal function. If warm temperatures are not maintained during administration, mannitol can precipitate into crystals, causing vascular and end-organ damage. It is also possible for leakage of mannitol across the blood–brain barrier to cause a rebound increase in intracranial pressure (Tenny et al., 2022).
The client’s kidney function must be adequate to manage the increased diuresis that mannitol will produce. It should be avoided in clients with anuria or previous renal damage caused by mannitol, and it should be used with caution in clients with decreased renal function. It should not be used for clients who are severely dehydrated or who have existing electrolyte abnormalities that could be exacerbated by its administration. Mannitol should not be used in clients with congestive heart failure or pulmonary edema.
Safety Alert
Osmotic Diuretics
Renal function should be monitored in all clients receiving mannitol. Acute renal failure can occur not only in clients with preexisting renal disease but also in clients with normal renal function.
(Source: DailyMed, Mannitol , 2023)
Table 34.4 is a drug prototype table for osmotic diuretics featuring mannitol. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
|
Drug Class
Osmotic diuretic Mechanism of Action Increases osmotic pressure, which increases urinary output |
Drug Dosage
Increased intracranial pressure: Bolus injection of 0.25 g/kg IV every 6–8 hours as needed. Increased intraocular pressure: 0.25–2 g/kg IV of 20% solution over at least 30 minutes. |
|
Indications
Increased intracranial pressure Increased intraocular pressure Therapeutic Effects Relieves edema Increases urinary output |
Drug Interactions
Acetaminophen Acetylsalicylic acid (aspirin) Acyclovir Use with caution with all nephrotoxic drugs due to the cumulative effect. Food Interactions Alcohol Black licorice |
|
Adverse Effects
Hypokalemia Hyponatremia Orthostatic hypotension Hypovolemia Azotemia Oliguria Agranulocytosis Hyperuricemia Heart failure |
Contraindications
Hypersensitivity Anuria Severe hypovolemia Preexisting pulmonary edema Intracranial bleeding Congestive heart failure Impaired renal function Existing electrolyte abnormalities |
Nursing Implications
The nurse should do the following for clients who are taking mannitol:
- Administer the medication through a dedicated IV line in a large central vein (DailyMed, Mannitol , 2023).
- Use only filtered tubing to administer the medication (DailyMed, Mannitol , 2023).
- Avoid administering mannitol simultaneously with blood products.
- Check the medication vial for the presence of crystals. If they are present, warm the solution to 140ºF, vigorously agitate the vial, and then cool the medication to body temperature before administering (DailyMed, Mannitol , 2023).
- Monitor the infusion site for signs of extravasation during administration.
- Carefully monitor the client’s fluid volume status by assessing vital signs and weight.
- Monitor lung sounds for congestion and other signs of heart failure or circulatory overload.
- Monitor laboratory values for electrolyte imbalances.
- Provide client teaching regarding the drug and when to call the health care provider. See below for client teaching guidelines.
Clinical Tip
Mannitol Administration
Monitor the insertion site during the infusion for signs of extravasation because extravasation of mannitol can result in the development of compartment syndrome in the arm in which it is infusing. Compartment syndrome is a state of increased pressure in a closed compartment containing bone and fascia, resulting in tissue injury.
(Source: DailyMed, Mannitol , 2023)
Client Teaching Guidelines
The client taking an osmotic diuretic should:
- Avoid potential food interactions, including black licorice and alcohol.
- Report any pain, especially headaches or pain at the infusion site.
- Report changes in vision (in clients being treated for increased intraocular pressure).


15.3: Introduction to the Second Law of Thermodynamics - Heat Engines and their Efficiency
Learning Objectives
By the end of this section, you will be able to:
- State the expressions of the second law of thermodynamics.
- Calculate the efficiency and carbon dioxide emission of a coal-fired electricity plant, using second law characteristics.
- Describe and define the Otto cycle.
The second law of thermodynamics deals with the direction taken by spontaneous processes. Many processes occur spontaneously in one direction only—that is, they are irreversible, under a given set of conditions. Although irreversibility is seen in day-to-day life—a broken glass does not resume its original state, for instance—complete irreversibility is a statistical statement that cannot be seen during the lifetime of the universe. More precisely, an irreversible process is one that depends on path. If the process can go in only one direction, then the reverse path differs fundamentally and the process cannot be reversible. For example, as noted in the previous section, heat involves the transfer of energy from higher to lower temperature. A cold object in contact with a hot one never gets colder, transferring heat to the hot object and making it hotter. Furthermore, mechanical energy, such as kinetic energy, can be completely converted to thermal energy by friction, but the reverse is impossible.  Yet another example is the expansion of a puff of gas introduced into one corner of a vacuum chamber. The gas expands to fill the chamber, but it never regroups in the corner. The random motion of the gas molecules could take them all back to the corner, but this is never observed to happen. (See Figure \(\PageIndex{2}\))
The fact that certain processes never occur suggests that there is a law forbidding them to occur. The first law of thermodynamics would allow them to occur—none of those processes violate conservation of energy. The law that forbids these processes is called the second law of thermodynamics. We shall see that the second law can be stated in many ways that may seem different, but which in fact are equivalent. Like all natural laws, the second law of thermodynamics gives insights into nature, and its several statements imply that it is broadly applicable, fundamentally affecting many apparently disparate processes.
The already familiar direction of heat transfer from hot to cold is the basis of our first version of the second law of thermodynamics .
The Second Law of Thermodynamics (first expression)
Heat transfer occurs spontaneously from higher- to lower-temperature bodies but never spontaneously in the reverse direction.
Another way of stating this: It is impossible for any process to have as its sole result heat transfer from a cooler to a hotter object.
Heat Engines
Now let us consider a device that uses heat transfer to do work. As noted in the previous section, such a device is called a heat engine, and one is shown schematically in \(\PageIndex{3}\)(b). Gasoline and diesel engines, jet engines, and steam turbines are all heat engines that do work by using part of the heat transfer from some source. Heat transfer from the hot object (or hot reservoir) is denoted as \(Q_f\), while heat transfer into the cold object (or cold reservoir) is \(Q_c\), and the work done by the engine is \(W\). The temperatures of the hot and cold reservoirs are \(T_h\) and \(T_c\), respectively.
Because the hot reservoir is heated externally, which is energy intensive, it is important that the work is done as efficiently as possible. In fact, we would like \(W\) to equal \(Q_h\) and for there to be no heat transfer to the environment \((Q_c = 0)\). Unfortunately, this is impossible. The second law of thermodynamics also states, with regard to using heat transfer to do work (the second expression of the second law):
The Second Law of Thermodynamics (second expression)
It is impossible in any system for heat transfer from a reservoir to completely convert to work in a cyclical process in which the system returns to its initial state.
A cyclical process brings a system, such as the gas in a cylinder, back to its original state at the end of every cycle. Most heat engines, such as reciprocating piston engines and rotating turbines, use cyclical processes. The second law, just stated in its second form, clearly states that such engines cannot have perfect conversion of heat transfer into work done. Before going into the underlying reasons for the limits on converting heat transfer into work, we need to explore the relationships among \(W, \, Q_h\), and \(Q_c\) and to define the efficiency of a cyclical heat engine. As noted, a cyclical process brings the system back to its original condition at the end of every cycle. Such a system’s internal energy \(U\) is the same at the beginning and end of every cycle—that is, \(\Delta U = 0\). The first law of thermodynamics states that
\[\Delta U = Q - W,\]
where \(Q\) is the net heat transfer during the cycle \((Q = Q_h - Q_c)\) and \(W\) is the net work done by the system.
Thus the net work done by the system equals the net heat transfer into the system, or
\[W = Q_h - Q_c \, (cyclical \, process),\]
just as shown schematically in Figure \(\PageIndex{3}\)(b). The problem is that in all processes, there is some heat transfer \(Q_c\) to the environment—and usually a very significant amount at that.
In the conversion of energy to work, we are always faced with the problem of getting less out than we put in. We define conversion efficiency \(Eff\) to be the ratio of useful work output to the energy input (or, in other words, the ratio of what we get to what we spend). In that spirit, we define the efficiency of a heat engine to be its net work output \(W\) divided by heat transfer to the engine \(Q_h\), that is,
\[Eff = \dfrac{W}{Q_h}.\]
Since \(W = Q_h - Q_c\) in a cyclical process, we can also express this as
\[Eff = \dfrac{Q_h - Q_c}{Q_h} = 1 - \dfrac{Q_c}{Q_h} \, (cyclical \, process),\]
making it clear that an efficiency of 1, or 100%, is possible only if there is no heat transfer to the environment \((Q_c = 0)\). Note that all \(Q\)s are positive. The direction of heat transfer is indicated by a plus or minus sign. For example, \(Q-c\) is out of the system and so is preceded by a minus sign.
Example \(\PageIndex{1}\): Daily Work Done by a Coal-Fired Power Station, Its Efficiency and Carbon Dioxide Emissions
A coal-fired power station is a huge heat engine. It uses heat transfer from burning coal to do work to turn turbines, which are used to generate electricity. In a single day, a large coal power station has \(2.50 \times 10^{14} \, J\) of heat transfer from coal and \(1.48 \times 10^14 \, J\) of heat transfer into the environment. (a) What is the work done by the power station? (b) What is the efficiency of the power station? (c) In the combustion process, the following chemical reaction occurs: \(C + O_2 \rightarrow CO_2\) This implies that every 12 kg of coal puts 12 kg + 16 kg + 16 kg = 44 kg of carbon dioxide into the atmosphere. Assuming that 1 kg of coal can provide \(2.5 \times 10^6 \, J\) of heat transfer upon combustion, how much \(CO_2\) is emitted per day by this power plant?
Strategy for (a)
We can use \(W = Q_h - Q_c\) to find the work output \(W\),
assuming a cyclical process is used in the power station. In this process, water is boiled under pressure to form high-temperature steam, which is used to run steam turbine-generators, and then condensed back to water to start the cycle again.
Solution for (a)
Work output is given by:
\[W = Q_h - Q_c. \nonumber\]
Substituting the given values:
\[\begin{align*} W &= 2.50 \times 10^14 \, J - 1.48 \times 10^{14} \, J \\[4pt] &= 1.02 \times 10^{14} \, J. \end{align*}\]
Strategy for (b)
The efficiency can be calculated with \(Eff = \dfrac{W}{Q_h}\) since \(Q_H\) is given and work \(W\) was found in the first part of this example.
Solution for (b)
Efficiency is given by \(Eff = \dfrac{W}{Q_h}\). The work \(W\) was just found to be \(1.01 \times 10^{14}\), and \(Q_h\) is given, so the efficiency is
\[Eff = \dfrac{1.01 \times 10^{14} \, J}{2.50 \times 10^{14} \, J} = 0.408, \, or \, 40.8\%\]
Strategy for (c)
The daily consumption of coal is calculated using the information that each day there is
\[\dfrac{2.50 \times 10^{14} \, J}{2.50 \times 10^6 \, J/kg} = 1.0 \times 10^8 \, kg. \nonumber\]
Assuming that the coal is pure and that all the coal goes toward producing carbon dioxide, the carbon dioxide produced per day is
\[1.0 \times 10^8 \, kg \, coal \times \dfrac{44 \, kg \, CO_2}{12 \, kg \, coal} = 3.7 \times 10^8 \, kg \, CO_2. \nonumber\]
This is 370,000 metric tons of \(CO2\) produced every day.
Discussion
If all the work output is converted to electricity in a period of one day, the average power output is 1180 MW (this is left to you as an end-of-chapter problem). This value is about the size of a large-scale conventional power plant. The efficiency found is acceptably close to the value of 42% given for coal power stations. It means that fully 59.2% of the energy is heat transfer to the environment, which usually results in warming lakes, rivers, or the ocean near the power station, and is implicated in a warming planet generally. While the laws of thermodynamics limit the efficiency of such plants—including plants fired by nuclear fuel, oil, and natural gas—the heat transfer to the environment could be, and sometimes is, used for heating homes or for industrial processes. The generally low cost of energy has not made it economical to make better use of the waste heat transfer from most heat engines. Coal-fired power plants produce the greatest amount of \(\ce{CO2}\) per unit energy output (compared to natural gas or oil), making coal the least efficient fossil fuel.
With the information given in Example \(\PageIndex{1}\), we can find characteristics such as the efficiency of a heat engine without any knowledge of how the heat engine operates, but looking further into the mechanism of the engine will give us greater insight. Figure \(\PageIndex{4}\) illustrates the operation of the common four-stroke gasoline engine. The four steps shown complete this heat engine’s cycle, bringing the gasoline-air mixture back to its original condition.
The Otto cycle shown in Figure \(\PageIndex{5a}\) is used in four-stroke internal combustion engines, although in fact the true Otto cycle paths do not correspond exactly to the strokes of the engine.
The adiabatic process AB corresponds to the nearly adiabatic compression stroke of the gasoline engine. In both cases, work is done on the system (the gas mixture in the cylinder), increasing its temperature and pressure. Along path BC of the Otto cycle, heat transfer \(Q_h\) into the gas occurs at constant volume, causing a further increase in pressure and temperature. This process corresponds to burning fuel in an internal combustion engine, and takes place so rapidly that the volume is nearly constant. Path CD in the Otto cycle is an adiabatic expansion that does work on the outside world, just as the power stroke of an internal combustion engine does in its nearly adiabatic expansion. The work done by the system along path CD is greater than the work done on the system along path AB, because the pressure is greater, and so there is a net work output. Along path DA in the Otto cycle, heat transfer \(Q_c\)
from the gas at constant volume reduces its temperature and pressure, returning it to its original state. In an internal combustion engine, this process corresponds to the exhaust of hot gases and the intake of an air-gasoline mixture at a considerably lower temperature. In both cases, heat transfer into the environment occurs along this final path.
The net work done by a cyclical process is the area inside the closed path on a \(PV\) diagram, such as that inside path ABCDA in Figure \(\PageIndex{5}\). Note that in every imaginable cyclical process, it is absolutely necessary for heat transfer from the system to occur in order to get a net work output. In the Otto cycle, heat transfer occurs along path DA. If no heat transfer occurs, then the return path is the same, and the net work output is zero. The lower the temperature on the path AB, the less work has to be done to compress the gas. The area inside the closed path is then greater, and so the engine does more work and is thus more efficient. Similarly, the higher the temperature along path CD, the more work output there is (Figure \(\PageIndex{6}\). So efficiency is related to the temperatures of the hot and cold reservoirs. In the next section, we shall see what the absolute limit to the efficiency of a heat engine is, and how it is related to temperature.
Summary
- The two expressions of the second law of thermodynamics are: (i) Heat transfer occurs spontaneously from higher- to lower-temperature bodies but never spontaneously in the reverse direction; and (ii) It is impossible in any system for heat transfer from a reservoir to completely convert to work in a cyclical process in which the system returns to its initial state.
- Irreversible processes depend on path and do not return to their original state. Cyclical processes are processes that return to their original state at the end of every cycle.
- In a cyclical process, such as a heat engine, the net work done by the system equals the net heat transfer into the system, or \(W = Q_h - Q_c\), where \(Q_h\) is the heat transfer from the hot object (hot reservoir), and \(Q_c\) is the heat transfer into the cold object (cold reservoir).
- Efficiency can be expressed as \(Eff = \dfrac{W}{Q_h}\), the ratio of work output divided by the amount of energy input.
- The four-stroke gasoline engine is often explained in terms of the Otto cycle, which is a repeating sequence of processes that convert heat into work.
Glossary
- irreversible process
- any process that depends on path direction
- second law of thermodynamics
- heat transfer flows from a hotter to a cooler object, never the reverse, and some heat energy in any process is lost to available work in a cyclical process
- cyclical process
- a process in which the path returns to its original state at the end of every cycle
- Otto cycle
- a thermodynamic cycle, consisting of a pair of adiabatic processes and a pair of isochoric processes, that converts heat into work, e.g., the four-stroke engine cycle of intake, compression, ignition, and exhaust


6.3E: Logarithmic Functions (Exercises)
13. Rewrite \(\log _{17}(4913)=x\) as an equivalent exponential equation.
14. Rewrite \(\ln (s)=t\) as an equivalent exponential equation.
15. Rewrite \(a^{- \frac{2}{5}}=b\) as an equivalent logarithmic equation.
16. Rewrite \(e^{-3.5}=h\) as an equivalent logarithmic equation.
17. Solve for \(x\) if \(\log _{64}(x)=\frac{1}{3}\) by converting to exponential form.
18. Evaluate \(\log _{5}\left(\frac{1}{125}\right)\) without using a calculator.
19. Evaluate \(\log (0.000001)\) without using a calculator.
20. Evaluate \(\log (4.005)\) using a calculator. Round to the nearest thousandth.
21. Evaluate \(\ln \left(e^{-0.8648}\right)\) without using a calculator.
22. Evaluate \(\ln (\sqrt[3]{18})\) using a calculator. Round to the nearest thousandth.