$$\text{Atomic mass} = \text{Number of protons} + \text{Number of neutrons}$$

Question 1

Which of the following statements best explains why ice floats on water, and why this property is crucial for aquatic life in cold climates?

Accepted Answer

Ice is less dense than liquid water due to the expansion of water molecules upon freezing, allowing it to float and insulate aquatic life below.

Question 2

A radioactive isotope of carbon, carbon-14, is used in dating ancient artifacts. If carbon-14 has 6 protons, how many neutrons does it have?

Accepted Answer

8 neutrons

Question 3

Which property of water is NOT directly attributable to hydrogen bonding between water molecules?

Accepted Answer

Polarity

Question 4

If a solution has a pH of 5 and another has a pH of 7, how many times more acidic is the pH 5 solution compared to pH 7?

Accepted Answer

$$10^2 = 100$ times

Question 5

Which of the following best describes an ionic bond?

Accepted Answer

Atoms donate or take electrons, forming ions that are attracted to each other.

Question 6

A molecule of water ($$\mathrm{H_2O}) is $$formed when:

Accepted Answer

One oxygen atom and two hydrogen atoms share electrons unequally, resulting in a polar covalent bond.

Question 7

Which of the following is a real-world application of radioactive isotopes?

Accepted Answer

Dating ancient artifacts and killing cancer cells.

Question 8

What is the correct formula for calculating atomic mass?

Accepted Answer

$$	ext{Atomic mass} = 	ext{Number of protons} + 	ext{Number of neutrons}$$

Question 9

Which of the following best explains why water is an excellent solvent for ionic and polar substances?

Accepted Answer

Water's polarity allows it to surround and dissociate ions and polar molecules.

Question 10

Which subatomic particle determines the chemical properties of an atom?

Accepted Answer

Electron

Question 11

Sulfur has an atomic number of 16. How many electron shells does sulfur have, and how many electrons are in its outer shell?

Accepted Answer

3 shells, 6 electrons in outer shell

Question 12

Which of the following is NOT matter?

Accepted Answer

Light

Question 13

What is the main reason water can moderate temperature so effectively in living organisms?

Accepted Answer

Water has a high heat capacity due to hydrogen bonding.

Question 14

Which of the following best describes the octet rule?

Accepted Answer

Atoms are stable when their outer shell contains eight electrons.

Question 15

Which of the following is a multi-step chemical reaction involving water as a product?

Accepted Answer

2 $$\mathrm{H_2$}$$ + $$\mathrm{O_2$}$$ → 2 $$\mathrm{H_2O}$$

Question 16

Which of the following is a consequence of water's cohesive behavior in plants?

Accepted Answer

Water molecules stick together, enabling upward movement through plant vessels.

Question 17

Household ammonia has a pH of 11 and egg whites have a pH of 8. How much more basic is ammonia than egg whites?

Accepted Answer

$$10^3 = 1000$ times

Question 18

Which of the following is a correct statement about chemical equilibrium?

Accepted Answer

At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction.

Question 19

Which of the following best describes a hydrogen bond?

Accepted Answer

A bond formed between a hydrogen atom in a covalent bond and a negatively charged atom.

Question 20

Tomatoes have a pH of 4 and lemon juice has a pH of 2. How much more acidic is lemon juice than tomatoes?

Accepted Answer

$$10^2 = 100$ times

Chemistry of Life: Foundations for Biology

Study Guide - Practice Questions