AP Biology Chapter 2 Review Questions

Why can some insects walk on water?

Because they do not break the surface tension of the water.

What makes ionic bonds different from covalent bonds?

Ionic bonds result when electrons are tranfered between atoms. Covalent bonds result when valence electrons are shared between atoms.

If xenon has an atomic number of 54 and a mass number of 108, how many neutrons does it have? a. 54 b. 27 c. 100 d. 108

a. 54

Which type of bond represents a weak chemical bond? a. hydrogen bond b. atomic bond c. covalent bond d. nonpolar covalent bond

a. hydrogen bond

Which of the following statements is true? a. Acids and bases cannot mix together. b. Acids and bases will neutralize each other. c. Acids, but not bases, can change the pH of a solution. d. Acids donate hydroxide ions (OH-); bases donate hydrogen ions (H+).

b. Acids and bases will neutralize each other.

A molecule that binds up excess hydrogen ions in a solution is called a(n) ________. a. acid b. isotope c. base d. donator

c. base

What property of carbon makes it essential for organic life?

Carbon is unique and found in all living things because it can form up to four covalent bonds between atoms or molecules. These can be nonpolar covalent bonds, and they allow for the formation of long chains of carbon molecules that combine to form proteins and DNA.

How many neutrons do carbon-12 and carbon-13 have, respectively?

Carbon-12: 6 Neutrons Carbon-13: 7 Neutrons

An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration. Looking at this figure, how many electrons do elements in group 1 need to lose in order to achieve a stable electron configuration? How many electrons do elements in groups 14 and 17 need to gain to achieve a stable configuration?

Group 1 needs to lose 1 electron. Group 14 needs to gain 4 electrons. Group 17 needs to gain 1 electron.

Why are hydrogen bonds and van der Waals interactions necessary for cells?

Hydrogen bonds are also responsible for zipping together the DNA double helix. The van der Waals interactons—along with ionic, covalent, and hydrogen bonds—contribute to the three-dimensional structure of the proteins in our cells that is necessary for their proper function.

Compare and contrast saturated and unsaturated triglycerides.

Saturated triglycerides contain no double bonds between carbon atoms; they are usually solid at room temperature. Unsaturated triglycerides contain at least one double bond between carbon atoms and are usually liquid at room temperature.

When acids are added to a solution, the pH should ________. a. decrease b. increase c. stay the same d. cannot tell without testing

b. increase

Which of the following statements is false? a. Molecules with the formulas CH3CH2COOH and C3H6O2 could be structural isomers. b. Molecules must have a double bond to be cis-trans isomers. c. To be enantiomers, a molecule must have at least three different atoms or groups connected to a central carbon. d. To be enantiomers, a molecule must have at least four different atoms or groups connected to a central carbon.

c. To be enantiomers, a molecule must have at least three different atoms or groups connected to a central carbon. Is False

Potassium has an atomic number of 19. What is its electron configuration? a. shells 1 and 2 are full, and shell 3 has nine electrons b. shells 1, 2 and 3 are full and shell 4 has three electrons c. shells 1, 2 and 3 are full and shell 4 has one electron d. shells 1, 2 and 3 are full and no other electrons are present

c. shells 1, 2 and 3 are full and shell 4 has one electron

Which of the following statements is not true? a. Water is polar. b. Water stabilizes temperature. c. Water is essential for life. d. Water is the most abundant molecule in the Earth's atmosphere.

d. Water is the most abundant molecule in the Earth's atmosphere.

Each carbon molecule can bond with as many as________ other atom(s) or molecule(s). a. one b. two c. six d. four

d. four

Atoms that vary in the number of neutrons found in their nuclei are called ________. a. ions b. neutrons c. neutral atoms d. isotopes

d. isotopes

Discuss how buffers help prevent drastic swings in pH.

They readily absorb excess H+ or OH-

Which of the following is not a functional group that can bond with carbon? a. sodium b. hydroxyl c. phosphate d. carbonyl

a. sodium