Question 1

Which property of water explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice create an open crystal structure, making ice less dense than liquid water.

Question 2

Why is sweating an effective way for humans to cool off?

Accepted Answer

Water has a high heat of vaporization, so it absorbs a lot of energy when it evaporates.

Question 3

Which of the following best describes a buffer in biological systems?

Accepted Answer

A buffer minimizes changes in pH by accepting or donating protons.

Question 4

What is the main reason why water is an excellent solvent for ionic and polar substances?

Accepted Answer

Water molecules form hydrogen bonds with ions and polar molecules due to their partial charges.

Question 5

Which of the following reactions is the reverse of a condensation (dehydration) reaction?

Accepted Answer

Hydrolysis

Question 6

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution? (Use $$[H^+] = 10$$^{-pH}$$)

Accepted Answer

$$[H^+] = 10$$^{-4}$$ M

Question 7

Which functional group acts as a base by attracting a proton?

Accepted Answer

Amino group

Question 8

Which of the following statements about chemical evolution is supported by Stanley Miller’s experiment?

Accepted Answer

Simple molecules with high free energy can form complex organic molecules when exposed to kinetic energy.

Question 9

Which property of water is primarily responsible for the formation of a meniscus in a glass tube?

Accepted Answer

Adhesion of water molecules to the glass surface

Question 10

Which of the following best explains why nonpolar molecules do not dissolve in water?

Accepted Answer

Nonpolar molecules are repelled by the partial charges of water and interact with each other through hydrophobic interactions.

Question 11

Which of the following is a characteristic of a spontaneous chemical reaction?

Accepted Answer

The products have lower potential energy and greater disorder (higher entropy) than the reactants.

Question 12

Which of the following best describes the role of van der Waals interactions in biological systems?

Accepted Answer

They stabilize clusters of hydrophobic molecules in aqueous environments.

Question 13

Which of the following functional groups is most likely to form disulfide bonds in proteins?

Accepted Answer

Sulfhydryl group

Question 14

If the pH of a solution changes from 6 to 4, how does the hydrogen ion concentration change?

Accepted Answer

It increases by a factor of 100.

Question 15

Which of the following statements about carbon is true?

Accepted Answer

Carbon atoms can form a limitless array of molecular shapes due to their four valence electrons.

Question 16

Which process is responsible for breaking down polymers into monomers in living organisms?

Accepted Answer

Hydrolysis

Question 17

Which of the following best explains why water has a high specific heat?

Accepted Answer

Many hydrogen bonds must be broken for water molecules to move faster.

Question 18

Which of the following is NOT a characteristic of life that was fulfilled after the original molecule acquired a membrane?

Accepted Answer

Lack of response to the environment

Question 19

Which of the following best describes the difference between adhesion and cohesion in water?

Accepted Answer

Cohesion is the attraction between like molecules (water to water); adhesion is the attraction between unlike molecules (water to glass).

Question 20

Which of the following statements about the Miller-Urey experiment is correct?

Accepted Answer

It provided evidence that complex organic molecules could form under conditions similar to early Earth.

Water and Carbon: The Chemical Basis of Life (Chapter 2 Study Notes)

Study Guide - Practice Questions