Question 1

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

Accepted Answer

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

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 overall polarity allow it to form hydrogen bonds with charged and polar molecules.

Question 3

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

Accepted Answer

Amino group

Question 4

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

Accepted Answer

$$1 	imes 10$$^{-5}$$ \, M$$

Question 5

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

Accepted Answer

Sweat absorbs heat as it evaporates because water has a high heat of vaporization.

Question 6

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 7

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 8

Which of the following best describes a spontaneous chemical reaction?

Accepted Answer

A reaction that proceeds on its own, with products having lower potential energy and greater disorder (higher entropy) than reactants.

Question 9

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 10

Which of the following is a correct statement about buffers in biological systems?

Accepted Answer

Buffers minimize changes in pH, helping maintain homeostasis.

Question 11

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

Accepted Answer

Nonpolar molecules lack charges and cannot form hydrogen bonds with water.

Question 12

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

Accepted Answer

Sulfhydryl group

Question 13

What is the main reason water has a high specific heat?

Accepted Answer

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

Question 14

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

Accepted Answer

A reaction that joins monomers to form polymers, releasing a water molecule.

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 of the following is a property of water that is critical for life and is a direct result of hydrogen bonding?

Accepted Answer

Water has high cohesion, leading to surface tension.

Question 17

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

Accepted Answer

They increase the stability of clustered hydrophobic molecules in water.

Question 18

Which of the following statements about acids and bases is correct?

Accepted Answer

Acids have a pH less than 7, while bases have a pH greater than 7.

Question 19

Which of the following is a direct result of the polarity of water molecules?

Accepted Answer

Water can dissolve both ionic and polar substances.

Question 20

Which of the following best explains why the concentration of free protons in pure water is $$1 	imes 10$$^{-7}$$ \, M$$?

Accepted Answer

A small fraction of water molecules dissociate, producing equal concentrations of $$H^+$$ and $$OH^-$$ ions.

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

Study Guide - Practice Questions