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

Question 1

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

Accepted Answer

Water forms a relatively open crystal structure as it freezes, making it less dense than liquid water.

Question 2

Which of the following best describes why water is an excellent solvent for polar and ionic substances?

Accepted Answer

Water molecules have partial charges that interact with charged or polar solutes, forming hydrogen bonds.

Question 3

A scientist adds a base to a solution. What happens to the concentration of hydronium ions ($$H_3O^+) $$and the pH?

Accepted Answer

Hydronium ion concentration decreases and pH increases.

Question 4

Which of the following is a direct result of water’s high specific heat in living organisms?

Accepted Answer

Organisms can survive in environments with rapidly fluctuating temperatures.

Question 5

Which functional group acts as a base by attracting protons?

Accepted Answer

Amino group

Question 6

Why do hydrophobic molecules tend to cluster together in aqueous solutions?

Accepted Answer

They interact via van der Waals interactions, increasing the stability of the cluster.

Question 7

Which of the following statements about chemical evolution is correct?

Accepted Answer

It refers to the formation of increasingly complex carbon-containing substances that eventually led to self-replicating molecules.

Question 8

Which property of water is primarily responsible for the phenomenon of surface tension?

Accepted Answer

Cohesion due to hydrogen bonding between water molecules

Question 9

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

Accepted Answer

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

Question 10

Which experiment provided evidence that complex organic molecules could be synthesized from simple molecules under early Earth conditions?

Accepted Answer

Stanley Miller’s spark-discharge experiment

Question 11

Which of the following best explains why sweating cools the human body?

Accepted Answer

Evaporation of sweat absorbs a large amount of energy due to water’s high heat of vaporization.

Question 12

Which of the following is NOT a characteristic of water that contributes to its role as the basis of life?

Accepted Answer

Water is nonpolar and uncharged.

Question 13

Which of the following statements about organic compounds is correct?

Accepted Answer

They contain carbon bonded to other elements and can have a limitless array of molecular shapes.

Question 14

Which process is responsible for linking monomers together to form polymers, and what is a byproduct of this reaction?

Accepted Answer

Condensation (dehydration) reaction; water is released.

Question 15

Which of the following best describes the role of buffers in biological systems?

Accepted Answer

Buffers minimize changes in pH, helping maintain homeostasis.

Question 16

Which two factors determine whether a chemical reaction will proceed spontaneously?

Accepted Answer

The products have lower potential energy and are less ordered than the reactants.

Question 17

Which functional group is most likely to form disulfide bonds, stabilizing protein structure?

Accepted Answer

Sulfhydryl group

Question 18

Which of the following best explains why ions and polar molecules dissolve readily in water?

Accepted Answer

Water’s partial charges interact with charged or polar solutes, stabilizing them in solution.

Question 19

Which of the following is a real-world example of water’s adhesive property?

Accepted Answer

Water climbing up a paper towel dipped in a glass of water.

Question 20

Which of the following statements about entropy in chemical reactions is correct?

Accepted Answer

Spontaneous reactions tend to increase the entropy of the system.

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

Study Guide - Practice Questions