$$[H^+] = 1 \times 10$$^{-5}$$ M

Question 1

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

Accepted Answer

Hydrogen bonds cause water molecules to pack less tightly in ice.

Question 2

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

Accepted Answer

Water’s bent shape and polar covalent bonds allow it to form hydrogen bonds with ions and polar molecules.

Question 3

A solution has a pH of 5. What is the concentration of hydrogen ions $$[H^+] in $$the solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-5}$$ M

Question 4

Which of the following functional groups acts as a base by attracting a proton?

Accepted Answer

Amino group

Question 5

Why does sweating cool your body effectively?

Accepted Answer

Water absorbs a large amount of energy to break hydrogen bonds during evaporation.

Question 6

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 7

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

Accepted Answer

Nonpolar molecules are repelled by water’s partial charges and cluster together due to hydrophobic interactions.

Question 8

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

Accepted Answer

Hydrolysis reactions

Question 9

A buffer is added to a solution. What is its primary function?

Accepted Answer

To minimize changes in pH when acids or bases are added

Question 10

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

Accepted Answer

Organisms can survive in environments with rapidly fluctuating temperatures.

Question 11

Which of the following best describes the role of functional groups in organic molecules?

Accepted Answer

They determine the chemical behavior and reactivity of organic molecules.

Question 12

Which of the following is true about the pH scale?

Accepted Answer

A solution with pH 4 has ten times more hydrogen ions than a solution with pH 5.

Question 13

Which of the following statements about carbon is correct?

Accepted Answer

Carbon can form up to four covalent bonds, allowing for a variety of molecular shapes.

Question 14

Which of the following best explains why water has a high surface tension?

Accepted Answer

Cohesion due to hydrogen bonding between water molecules at the surface.

Question 15

Which of the following reactions is responsible for linking monomers together to form polymers?

Accepted Answer

Condensation (dehydration) reactions

Question 16

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 environmental changes

Question 17

Which of the following best describes a spontaneous chemical reaction?

Accepted Answer

A reaction where products have lower potential energy and higher entropy than reactants.

Question 18

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 19

Which of the following statements about van der Waals interactions is correct?

Accepted Answer

They stabilize clusters of hydrophobic molecules in water.

Question 20

Which of the following best explains why buffers are important in biological systems?

Accepted Answer

They maintain relatively constant pH, which is crucial for enzyme function and cellular processes.

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

Study Guide - Practice Questions