Question 1

Which of the following statements correctly describes the difference between atomic number and mass number for an atom?

Accepted Answer

Atomic number is the number of protons, while mass number is the sum of protons and neutrons.

Question 2

A carbon atom has 6 protons and 6 neutrons. What is its mass number ($$M$$)?

Accepted Answer

$$M = 12$$

Question 3

Which property of water allows it to moderate temperature changes in organisms and the environment?

Accepted Answer

Water's high specific heat due to hydrogen bonding

Question 4

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice create a lattice structure that is less dense than liquid water.

Question 5

A sodium atom loses one electron to become a sodium ion ($$Na^+). $$What type of bond does it form with a chloride ion ($$Cl^-$$)?

Accepted Answer

Ionic bond

Question 6

Which of the following molecules is most likely to be hydrophobic?

Accepted Answer

A molecule with many nonpolar covalent bonds

Question 7

How many valence electrons does a nitrogen atom have?

Accepted Answer

5

Question 8

Which of the following best describes the role of surface tension in water?

Accepted Answer

It enables water to resist rupture when placed under stress.

Question 9

Which statement about covalent bonds is correct?

Accepted Answer

Covalent bonds involve the sharing of electrons between atoms.

Question 10

A water molecule ($$H_2O) is $$described as polar because:

Accepted Answer

The oxygen atom has a partial negative charge and the hydrogen atoms have partial positive charges.

Question 11

Which of the following is a consequence of water's cohesive properties?

Accepted Answer

Water can flow up from the roots to the tops of plants.

Question 12

Which of the following functional groups is found in alcohols?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 13

If an atom has 8 protons, 8 neutrons, and 8 electrons, what is its atomic number and mass number?

Accepted Answer

Atomic number = 8, Mass number = 16

Question 14

Which of the following best explains why water is an excellent solvent for ionic compounds?

Accepted Answer

Water's polarity allows it to surround and separate ions.

Question 15

Which of the following is true about isotopes of an element?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 16

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally, resulting in partial charges on atoms.

Question 17

Which of the following functional groups is most likely to act as an acid in water?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 18

Which of the following statements about hydrogen bonds is correct?

Accepted Answer

Hydrogen bonds form between the partial positive charge of hydrogen and the partial negative charge of another atom.

Question 19

A molecule of methane ($$CH_4) $$has which type of bonds between carbon and hydrogen?

Accepted Answer

Nonpolar covalent bonds

Question 20

Which of the following best explains why water has a high heat of vaporization?

Accepted Answer

A large amount of energy is required to break the hydrogen bonds between water molecules.

Atoms, Ions, Molecules, and Water: Foundations of Chemical Biology

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