Question 1

Which of the following elements is NOT among the four most abundant elements found in living cells?

Accepted Answer

Sulfur (S)

Question 2

What determines the chemical behavior of an atom?

Accepted Answer

The number of electrons in the outermost (valence) shell

Question 3

Which statement best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally, creating partial charges on the atoms

Question 4

Given the electronegativity values: $$O \u003e N \u003e C \approx H$$, which bond is most likely to be ionic?

Accepted Answer

Na-F

Question 5

Why does water remain a liquid at room temperature, unlike other small molecules?

Accepted Answer

Water molecules are held together by hydrogen bonds

Question 6

Which of the following best explains why oil does not dissolve in water?

Accepted Answer

Oil molecules are nonpolar and hydrophobic

Question 7

A molecule with the formula $$NH_3 ($$ammonia) is best described as:

Accepted Answer

Polar and hydrophilic

Question 8

Which of the following is a correct pairing of a biological macromolecule and its monomer?

Accepted Answer

Nucleic Acid – Nucleotide

Question 9

What type of bond is formed when electrons are completely transferred from one atom to another?

Accepted Answer

Ionic bond

Question 10

Which of the following statements about hydrogen bonds is TRUE?

Accepted Answer

Hydrogen bonds form between a partially positive hydrogen and a partially negative atom in a different molecule

Question 11

Which property of water is MOST directly responsible for its ability to dissolve many substances?

Accepted Answer

Its polarity

Question 12

A molecule of carbon dioxide ($$CO_2) is $$considered nonpolar and hydrophobic because:

Accepted Answer

Its linear symmetry causes the partial charges to cancel out

Question 13

Which of the following best describes the difference between covalent and ionic bonds?

Accepted Answer

Covalent bonds involve the sharing of electrons, while ionic bonds involve the transfer of electrons

Question 14

Which of the following molecules would you expect to be most soluble in water?

Accepted Answer

A molecule with many polar covalent bonds

Question 15

Which of the following is NOT a polymer?

Accepted Answer

Lipid

Question 16

A molecule contains several O-H bonds. Predict its behavior in water.

Accepted Answer

It will be hydrophilic and soluble

Question 17

Which of the following best explains why salt (NaCl) dissolves in water?

Accepted Answer

Water’s partial charges surround and separate the Na+ and Cl- ions

Question 18

Which of the following is a correct match between a macromolecule and its function?

Accepted Answer

Proteins – catalyze chemical reactions

Question 19

Which of the following is necessary for a hydrogen bond to form?

Accepted Answer

A hydrogen atom covalently bonded to a highly electronegative atom and a nearby partially negative atom

Question 20

Which of the following best describes why water is considered a polar molecule?

Accepted Answer

It has an uneven distribution of charge due to oxygen’s higher electronegativity

Chemistry of Life: Atomic Structure, Bonding, and Biological Macromolecules

Study Guide - Practice Questions