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

Question 1

Which of the following statements best explains why water is an efficient solvent for biological reactions?

Accepted Answer

Water molecules form hydrogen bonds with both polar and charged solutes, allowing them to dissolve easily.

Question 2

A radioactive isotope of carbon decays over time. What property of this isotope allows it to be used in radiometric dating?

Accepted Answer

It has a different number of neutrons, making it unstable and prone to decay.

Question 3

Which element is most likely to form four covalent bonds in organic molecules, and why?

Accepted Answer

Carbon, because it has four unpaired valence electrons.

Question 4

What is the main difference between a polar covalent bond and a nonpolar covalent bond?

Accepted Answer

Polar covalent bonds have electrons shared unequally, resulting in partial charges.

Question 5

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

Accepted Answer

Buffers minimize changes in pH, helping maintain homeostasis.

Question 6

If a solution has a pH of 4, what is the concentration of hydrogen ions ($$[H^+]) in $$moles per liter?

Accepted Answer

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

Question 7

Which of the following molecules would be least likely to dissolve in water?

Accepted Answer

A molecule with nonpolar covalent bonds.

Question 8

What is the mass of one mole of glucose ($$C_6H_{12}O_6$)? (Atomic weights: C = 12, H = 1, O = 16)

Accepted Answer

$$180 g/$$mol

Question 9

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

Accepted Answer

Amino group

Question 10

Which statement about chemical evolution is correct?

Accepted Answer

It refers to the formation of increasingly complex carbon-containing substances before biological evolution.

Question 11

A sodium atom loses an electron to become a sodium ion. What is the charge and classification of this ion?

Accepted Answer

Positive charge, cation

Question 12

Which property of water is most responsible for its ability to moderate temperature in living organisms?

Accepted Answer

Its ability to form hydrogen bonds

Question 13

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 14

What determines the number of covalent bonds an atom can form?

Accepted Answer

The number of unpaired electrons in its valence shell.

Question 15

Which of the following is true about the electron-sharing continuum in chemical bonds?

Accepted Answer

Nonpolar covalent bonds involve equal sharing, polar covalent bonds involve unequal sharing, and ionic bonds involve complete transfer of electrons.

Question 16

Which of the following best explains why carbon is the backbone of organic molecules?

Accepted Answer

Carbon can form four covalent bonds, allowing for a variety of molecular shapes and sizes.

Question 17

Which of the following molecules would be considered hydrophobic?

Accepted Answer

A molecule composed mostly of nonpolar covalent bonds.

Question 18

What is the main consequence of water's bent shape and polar covalent bonds?

Accepted Answer

Water molecules have partial charges, allowing them to form hydrogen bonds.

Question 19

Which of the following is a correct statement about acids and bases in water?

Accepted Answer

Acids increase the concentration of hydronium ions ($$H_3O^+$$), while bases decrease it.

Question 20

Which of the following best describes the process of hydrolysis?

Accepted Answer

Hydrolysis breaks a polymer into monomers by adding a water molecule.

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

Study Guide - Practice Questions