Question 1

Which of the following best describes an element?

Accepted Answer

A substance that cannot be broken down to other substances by chemical reactions.

Question 2

Sodium (Na) is a highly reactive metal, and chlorine (Cl) is a poisonous gas. When combined, they form table salt (NaCl). What does this illustrate?

Accepted Answer

Emergent properties arise when elements combine to form compounds.

Question 3

Which four elements make up approximately 96% of living matter?

Accepted Answer

Carbon, hydrogen, oxygen, and nitrogen

Question 4

What is the atomic number of an element?

Accepted Answer

The number of protons in the nucleus

Question 5

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 6

Which type of bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent bond

Question 7

What is electronegativity?

Accepted Answer

The attraction of an atom for the electrons in a covalent bond

Question 8

Which of the following molecules contains a nonpolar covalent bond?

Accepted Answer

CH$$_4$$

Question 9

Why is water considered a polar molecule?

Accepted Answer

Because the electrons are pulled closer to the oxygen atom, creating partial charges

Question 10

Which of the following best describes a hydrogen bond?

Accepted Answer

A bond formed when a partially positive hydrogen atom is attracted to a nearby partially negative atom

Question 11

What is the main significance of weak chemical bonds in biological macromolecules?

Accepted Answer

They allow for the dynamic formation and maintenance of the molecule's 3D shape.

Question 12

Which of the following is true about ionic bonds?

Accepted Answer

They result from the attraction between oppositely charged ions.

Question 13

A molecule's size and shape are important because:

Accepted Answer

They determine how biological molecules recognize and respond to one another.

Question 14

Which of the following interactions is responsible for the ability of a gecko to climb smooth surfaces?

Accepted Answer

Van der Waals interactions

Question 15

Which of the following best explains why morphine and endorphins can bind to the same receptors in the brain?

Accepted Answer

They have similar molecular shapes.

Question 16

Which of the following is a trace element required by living organisms?

Accepted Answer

Iron

Question 17

If an atom has an atomic number of 8 and a mass number of 18, how many neutrons does it have?

Accepted Answer

$$18 - 8 = 10$$

Question 18

Which of the following best describes a polar covalent bond?

Accepted Answer

A bond where one atom is more electronegative and electrons are shared unequally.

Question 19

Which statement about van der Waals interactions is correct?

Accepted Answer

They are attractions between molecules that are close together due to temporary charge differences.

Question 20

Which of the following is an example of a molecule with a double covalent bond?

Accepted Answer

O$$_2$$

Chapter 2: The Chemical Context of Life – Study Notes

Study Guide - Practice Questions