Question 1

Which of the following best explains why water is considered a polar molecule?

Accepted Answer

Because the oxygen atom has a higher electronegativity than hydrogen, resulting in an unequal sharing of electrons.

Question 2

A scientist is studying a solution with a pH of 4. Which of the following statements is correct regarding this solution?

Accepted Answer

It has a hydrogen ion concentration $$[H^+]$$ that is 1000 times greater than a solution with pH 7.

Question 3

Which of the following best describes the role of buffers in biological systems?

Accepted Answer

Buffers minimize changes in pH by accepting or donating hydrogen ions.

Question 4

A radioactive isotope of carbon, $$^{14}C$$, is used in medical imaging. Which statement about $$^{14}C is $$correct?

Accepted Answer

$$^{14}C$$ has 6 protons and 8 neutrons in its nucleus.

Question 5

Which of the following best explains why salt (NaCl) dissolves easily in water?

Accepted Answer

The polar water molecules surround and separate the positive sodium ions and negative chloride ions.

Question 6

Which property of water allows insects to walk on its surface, as seen in ponds and lakes?

Accepted Answer

Surface tension caused by cohesion between water molecules.

Question 7

A solution is made by dissolving 10 grams of glucose in 100 mL of water. In this scenario, which term best describes glucose?

Accepted Answer

Solute

Question 8

Which of the following statements about covalent bonds is correct?

Accepted Answer

Covalent bonds involve the sharing of electron pairs between atoms.

Question 9

Ocean acidification is a growing environmental concern. Which process directly contributes to ocean acidification?

Accepted Answer

Absorption of atmospheric $$CO_2 by $$seawater, forming carbonic acid.

Question 10

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 11

A patient is given a medication that acts as a base. What effect will this have on the patient's blood pH?

Accepted Answer

It will decrease the concentration of hydrogen ions $$[H^+]$$, increasing the pH.

Question 12

Which of the following is an example of a chemical reaction?

Accepted Answer

Hydrogen gas and oxygen gas combine to form water: $$2H_2 + O_2$ \rightarrow 2H_2O$$

Question 13

Which statement correctly describes the difference between atomic number and mass number?

Accepted Answer

Atomic number is the number of protons; mass number is the sum of protons and neutrons.

Question 14

Which of the following best explains why sweating cools the human body?

Accepted Answer

Evaporative cooling removes heat as water molecules with the highest energy leave the skin.

Question 15

Which of the following is a trace element essential for human health?

Accepted Answer

Iron (Fe)

Question 16

A molecule of methane ($$CH_4) is $$held together by which type of bond?

Accepted Answer

Nonpolar covalent bonds

Question 17

Which of the following best describes adhesion?

Accepted Answer

The attraction between water molecules and other substances.

Question 18

Which of the following is true about ions?

Accepted Answer

Ions are atoms or molecules that have gained or lost electrons.

Question 19

Which of the following best describes a solution?

Accepted Answer

A homogeneous mixture of a solute dissolved in a solvent.

Question 20

A student mixes hydrochloric acid (HCl) with sodium hydroxide (NaOH) in water. Which of the following best describes the resulting reaction?

Accepted Answer

An acid-base reaction producing water and salt: $$HCl + NaOH \rightarrow NaCl + H_2O$$

Essential Chemistry Vocabulary for General Biology

Study Guide - Practice Questions