Question 1

Which of the following best distinguishes organic compounds from inorganic compounds?

Accepted Answer

Organic compounds generally contain carbon atoms bonded together, forming the backbone of the molecule, while inorganic compounds do not.

Question 2

Which four elements make up more than 96% of the mass of most living organisms?

Accepted Answer

Oxygen, carbon, hydrogen, and nitrogen

Question 3

What is the atomic number of an element?

Accepted Answer

The number of protons in the nucleus

Question 4

A neutral atom of carbon-14 has how many protons, neutrons, and electrons?

Accepted Answer

6 protons, 8 neutrons, 6 electrons

Question 5

Which statement best explains why radioisotopes are useful in medical imaging?

Accepted Answer

They have unstable nuclei that emit energy and particles, which can be detected by imaging equipment.

Question 6

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak attraction between a slightly positive hydrogen atom and a strongly electronegative atom, such as oxygen or nitrogen.

Question 7

Why does water have a high surface tension?

Accepted Answer

Because of the hydrogen bonds that form between water molecules at the surface.

Question 8

Which property of water allows it to move upward through the vessels of plants against gravity?

Accepted Answer

Cohesion and adhesion (capillary action)

Question 9

What happens when an ionic compound such as NaCl dissolves in water?

Accepted Answer

The ionic bonds are broken as the ions interact with the polar water molecules.

Question 10

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

Accepted Answer

Oil molecules are nonpolar and do not form hydration spheres with water.

Question 11

A molecule of water (H$$_2O) is $$held together by which type of bond?

Accepted Answer

Polar covalent bonds

Question 12

Which of the following equations correctly represents the process of photosynthesis?

Accepted Answer

$$6CO_2 + 6H_2O + 	ext{energy} ightarrow C_6H_{12}O_6$ + 6O_2$$

Question 13

Which of the following is true about valence electrons?

Accepted Answer

They determine the chemical behavior of an atom.

Question 14

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule is composed of two or more atoms chemically bonded together, while a compound is a molecule composed of two or more different elements.

Question 15

Which of the following is a real-life application of radioisotopes in medicine?

Accepted Answer

They are used as tracers in PET scans to detect metabolic activity.

Question 16

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 17

Which type of chemical bond is the strongest under physiological conditions?

Accepted Answer

Covalent bond

Question 18

What is the main reason that water is considered a temperature-stabilizing molecule?

Accepted Answer

Water can absorb and release large amounts of heat with only a slight change in its own temperature.

Question 19

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

Accepted Answer

Hydrogen bonds in ice hold water molecules farther apart, making ice less dense than liquid water.

Question 20

Which of the following is a property of water that is critical for life?

Accepted Answer

Water can dissolve a wide variety of substances due to its polarity.

Atoms, Molecules, and the Chemical Basis of Life: Study Notes

Study Guide - Practice Questions