Question 1

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

Accepted Answer

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

Question 2

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

Accepted Answer

Carbon, Hydrogen, Oxygen, Nitrogen

Question 3

An atom of sodium (Na) has 11 protons, 12 neutrons, and 11 electrons. What is its atomic mass in Daltons ($$Da$$)?

Accepted Answer

$$23 \, Da$$

Question 4

Which statement about isotopes is correct?

Accepted Answer

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

Question 5

Which of the following best explains why oxygen forms polar covalent bonds with hydrogen in water ($$H_2O$$)?

Accepted Answer

Oxygen has a much higher electronegativity than hydrogen, causing electrons to be shared unequally.

Question 6

Which type of chemical bond is formed when one atom donates an electron to another atom, resulting in oppositely charged ions that attract each other?

Accepted Answer

Ionic bond

Question 7

A radioactive isotope differs from a stable isotope in that it:

Accepted Answer

Emits subatomic particles and/or radiation to become stable.

Question 8

Which of the following best describes the octet rule?

Accepted Answer

Atoms are stable when their outermost shell contains eight electrons.

Question 9

Which of the following is true about hydrogen bonds?

Accepted Answer

They form between a hydrogen atom in a polar molecule and an electronegative atom in another polar molecule.

Question 10

Given the chemical equation $$CH_4 + 2O_2$$ \rightarrow $$CO_2 + 2H_2O$, which are the reactants?

Accepted Answer

$$CH_4$$ and $$2O_2$$

Question 11

Which of the following best describes a catalyst in a chemical reaction?

Accepted Answer

An agent that increases the reaction rate without being consumed.

Question 12

If an atom has 6 protons, 8 neutrons, and 6 electrons, what is its atomic number and atomic mass?

Accepted Answer

Atomic number: 6, Atomic mass: $$14 \, Da$$

Question 13

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

Accepted Answer

Iron (Fe)

Question 14

What determines the chemical properties of an element?

Accepted Answer

The number of valence electrons in the outermost shell.

Question 15

Which of the following best describes Van der Waals interactions?

Accepted Answer

Temporary bonds within a polar molecule due to momentary charges from electron location.

Question 16

Which of the following elements is NOT considered essential for life?

Accepted Answer

Arsenic (As)

Question 17

What is the net charge of a neutral atom?

Accepted Answer

Zero

Question 18

Which of the following best explains why noble gases like Neon (Ne) do not readily form chemical bonds?

Accepted Answer

They have a full valence shell of electrons.

Question 19

Which of the following is true about chemical equilibrium?

Accepted Answer

The rate of the forward reaction equals the rate of the backward reaction.

Question 20

Which of the following bonds is most likely to be found in a molecule of methane ($$CH_4$$)?

Accepted Answer

Nonpolar covalent bonds

The Chemical Context of Life: Study Notes for General Biology

Study Guide - Practice Questions

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