In order to grasp the concept of molar mass calculations it is important to understand the molar unit. The mole also called mol is the basic unit of measurement in chemistry. By definition, in modern chemistry, one mole represents the number of carbon atoms in exactly 12 grams of carbon 12 isotope.
Fetal development during the first trimester. The most dramatic changes and development for your baby occur during the first trimester. Itâs also during this time that the fetus is the most susceptible to damage from alcohol, drugs, certain medications, and illnesses.
Other highlights of the third trimester. 1  By the end of the trimester, your baby has eyelashes and eyebrows and may have a full head of hair. Or, he or she may be born bald. 2  The white waxy substance and fine hair that covered and protected your baby's skin in the second trimester has begun to fall off.