$$[H^+] = 1 \times 10$$^{-4}$$ M

Question 1

Which property of water allows ice to float on liquid water, and why is this significant for aquatic life in cold climates?

Accepted Answer

Water is less dense as a solid than as a liquid due to its open crystal structure, allowing ice to float and insulate aquatic environments.

Question 2

Which of the following best explains why sweating is an effective way for humans to cool off?

Accepted Answer

Water has a high heat of vaporization, so it absorbs a large amount of energy from the skin as it evaporates.

Question 3

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ M

Question 4

Which functional group is most likely to act as a base by attracting a proton?

Accepted Answer

Amino group

Question 5

Why do nonpolar molecules not dissolve in water?

Accepted Answer

Nonpolar molecules lack partial charges, so they do not interact favorably with water’s polarity.

Question 6

Which of the following best describes a condensation (dehydration) reaction?

Accepted Answer

A reaction in which two monomers are joined together, releasing a water molecule.

Question 7

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

Accepted Answer

Adhesion and cohesion

Question 8

What is the role of buffers in biological systems?

Accepted Answer

Buffers minimize changes in pH, helping maintain homeostasis.

Question 9

Which of the following statements about chemical evolution is correct?

Accepted Answer

Chemical evolution involves the formation of complex carbon-containing substances from simple molecules.

Question 10

Which of the following is true about the Miller-Urey experiment?

Accepted Answer

It demonstrated that amino acids could be synthesized from simple molecules under early Earth conditions.

Question 11

Which of the following best describes the relationship between entropy and spontaneous chemical reactions?

Accepted Answer

Spontaneous reactions occur when products are less ordered (higher entropy) and have lower potential energy than reactants.

Question 12

Which of the following is NOT a characteristic of water that makes it essential for life?

Accepted Answer

Water is denser as a solid than as a liquid.

Question 13

Which functional group is most likely to act as an acid by donating a proton?

Accepted Answer

Carboxyl group

Question 14

What is the main reason why water molecules are able to form hydrogen bonds with each other?

Accepted Answer

Water molecules have a bent shape and partial charges due to polar covalent bonds.

Question 15

Which of the following best explains why table salt (NaCl) dissolves readily in water?

Accepted Answer

Water’s partial charges interact with the charged ions of NaCl, stabilizing them in solution.

Question 16

Which process increases entropy and is energetically favorable in biological systems?

Accepted Answer

Hydrolysis of polymers into monomers

Question 17

Which of the following is a real-world example of surface tension in water?

Accepted Answer

A water strider walking on the surface of a pond

Question 18

Which of the following statements about organic compounds is correct?

Accepted Answer

Organic compounds are defined as molecules containing carbon bonded to other elements.

Question 19

Which of the following is true about the pH scale?

Accepted Answer

A solution with pH 5 has a hydrogen ion concentration ten times higher than a solution with pH 6.

Water and Carbon: The Chemical Basis of Life – Study Notes

Study Guide - Practice Questions