Q: Which of the following best describes the Henderson-Hasselbalch equation?

$$pH = pK_a + \log \frac{[\text{proton acceptor}]}{[\text{proton donor}]}$$

Question 1

Which property of water is primarily responsible for its ability to moderate temperature changes in living organisms?

Accepted Answer

Its high specific heat capacity

Question 2

Why does ice float on liquid water?

Accepted Answer

Ice forms a hexagonal lattice that is less dense than liquid water

Question 3

Which of the following best explains why sodium chloride (NaCl) dissolves readily in water?

Accepted Answer

Water's polarity allows it to form solvation spheres around the ions

Question 4

Which equation correctly represents the ionization constant ($$K_w) $$for water at 25°C?

Accepted Answer

$$K_w = [H^+][OH^-]$$

Question 5

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-5}$$ M. What is its pH?

Accepted Answer

pH = 5

Question 6

Which of the following statements about hydrogen bonds in water is CORRECT?

Accepted Answer

Hydrogen bonds are responsible for water's high heat of vaporization

Question 7

Which of the following best describes the Henderson-Hasselbalch equation?

Accepted Answer

$$pH = pK_a + \log \frac{[	ext{proton acceptor}]}{[	ext{proton donor}]}$$

Question 8

Which of the following molecules would be most soluble in water?

Accepted Answer

Glucose

Question 9

A buffer solution is prepared using acetic acid ($$pK_a = 4.8) $$and sodium acetate. If the concentrations of acetic acid and acetate are equal, what is the pH of the solution?

Accepted Answer

pH = 4.8

Question 10

Which of the following interactions is primarily responsible for the stabilization of protein secondary structure?

Accepted Answer

Hydrogen bonds

Question 11

Which of the following best explains why oil and water do not mix?

Accepted Answer

Oil is nonpolar and water is polar

Question 12

Which of the following is a correct statement about the pH and pKa relationship during the titration of a weak acid?

Accepted Answer

At the midpoint of titration, pH = pKa

Question 13

Which of the following is NOT a weak noncovalent interaction found in biological systems?

Accepted Answer

Covalent bonds

Question 14

Which of the following best describes the role of water in hydrolysis reactions?

Accepted Answer

Water acts as a nucleophile

Question 15

A patient’s blood pH drops below 7.4. According to the bicarbonate buffer system, what will happen to restore equilibrium?

Accepted Answer

The partial pressure of $$CO_2 in $$the lungs will increase

Question 16

Which of the following best explains why water is considered a polar molecule?

Accepted Answer

It has an uneven distribution of charge due to differences in electronegativity

Question 17

Which of the following is the correct formula for calculating pH?

Accepted Answer

$$pH = -\log [H^+]$$

Question 18

Which of the following statements about van der Waals forces is TRUE?

Accepted Answer

They are short-range interactions between dipoles

Question 19

Which of the following best describes a buffer solution?

Accepted Answer

A solution that resists changes in pH upon addition of small amounts of acid or base

Question 20

Which of the following is a real-life application of water’s high heat of vaporization?

Accepted Answer

Perspiration cooling the human body

Water: Structure, Properties, and Its Role in Biochemistry

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