Question

1. which of the following solutions is the weakest acid: a. a solution with a ph of 2.4 b. a solution with a ph of 6.4 c. a solution with a ph of 10.1 d. a solution with a ph of 8.6 e. a solution with a ph of 5.2 12. which of the following is the role of magnesium: a. it is needed to make functional thyroid hormones b. it is present in bone, and is an important cofactor for enzyme activity in a number of metabolic reactions c. it is the major extracellular cation in its ionic form, and is important for water balance, conduction of nerve impulses, and muscle contraction d. it is a component of the functional hemoglobin molecule that transports oxygen within red blood cells, as well as a component of some enzymes e. it is a major extracellular anion in its ionic form 13. which of the following statements about enzymes is true: a. they are required in large amounts in order to be effective b. they are not reusable c. they are biological catalysts d. they are stable at high temperatures e. they are carbohydrates 14. the most abundant element in the human body is: a. carbon b. oxygen c. nitrogen d. calcium e. hydrogen 15. when a pair of electrons is shared equally between two atoms, the bond formed is called a(n): a. hydrogen bond b. nonpolar covalent bond c. carbon bond d. polar covalent bond e. ionic bond 16. the most common steroid is: a. unsaturated fat b. triglyceride c. trans fat d. cholesterol e. phospholipid

Explanation:

1. The lower the pH, the stronger the acid. Among the given options, a pH closer to 7 indicates a weaker acid. A pH of 6.4 is the closest to 7 among the acid - pH values.
2. Magnesium is present in bone and acts as a co - factor for enzyme activity in many metabolic reactions.
3. Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are effective in small amounts, reusable, and are usually proteins (not carbohydrates) and can be denatured at high temperatures.
4. Oxygen is the most abundant element in the human body by mass, making up about 65% of the total body mass.
5. When electrons are shared equally between two atoms, a nonpolar covalent bond is formed. In polar covalent bonds, electrons are shared unequally, hydrogen bonds are intermolecular forces, and ionic bonds involve the transfer of electrons.
6. Cholesterol is the most common steroid in the body and is involved in many biological processes such as cell membrane structure and hormone synthesis.

Answer:

1. b. a solution with a pH of 6.4
2. b. it is present in bone, and is an important cofactor for enzyme activity in a number of metabolic reactions
3. c. they are biological catalysts
4. b. oxygen
5. b. nonpolar covalent bond
6. d. cholesterol