Question 1

Which subatomic particle determines the identity of an element?

Accepted Answer

Proton

Question 2

A neutral atom of carbon has 6 protons and 6 neutrons. What is its mass number?

Accepted Answer

$$12$$

Question 3

Variation in the number of which subatomic particle results in the formation of isotopes?

Accepted Answer

Neutrons

Question 4

Which of the following best describes why ice floats on water?

Accepted Answer

Hydrogen bonds in ice create a lattice that is less dense than liquid water.

Question 5

Which chemical bond is generally considered the strongest in biological systems?

Accepted Answer

Covalent bond

Question 6

How many electrons are required to fill the innermost (first) electron shell of an atom?

Accepted Answer

$$2$$

Question 7

Which property of water allows insects to walk on its surface?

Accepted Answer

Cohesion due to hydrogen bonding

Question 8

What is the pH of pure water at 25°C?

Accepted Answer

$$7$$

Question 9

Which of the following best explains why buffers are important in biological systems?

Accepted Answer

They absorb excess $$\mathrm{H^+} or$$ $$\mathrm{OH^-}$$ ions to maintain pH stability.

Question 10

A patient with untreated diabetes develops metabolic acidosis. Which of the following best describes their blood pH?

Accepted Answer

Below 7.35

Question 11

Which equation correctly represents the dissociation of water?

Accepted Answer

$$\mathrm{H_2O \rightarrow H^+ + OH^-}$$

Question 12

Which of the following is a direct consequence of ocean acidification?

Accepted Answer

Decrease in carbonate ion ($$\mathrm{CO_3$^{2-}}) $$concentration

Question 13

Which subatomic particle is primarily responsible for the formation of chemical bonds?

Accepted Answer

Electrons

Question 14

Which of the following best describes why water is an excellent solvent for salts?

Accepted Answer

Water's polarity allows it to surround and separate ions.

Question 15

Which of the following is the correct formula for calculating pH?

Accepted Answer

$$\mathrm{pH = -log[H^+]}$$

Question 16

Which of the following is a real-life example of a buffer system in the human body?

Accepted Answer

Bicarbonate in blood

Question 17

Which process is illustrated by the following equation: $$\mathrm{C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP + Heat}$$?

Accepted Answer

Cellular respiration

Question 18

Which of the following best explains why lipids form barriers in water?

Accepted Answer

Lipids are hydrophobic and do not mix with water.

Question 19

If the concentration of hydrogen ions in a solution increases by a factor of 100, what happens to the pH?

Accepted Answer

It decreases by 2 units

Question 20

Which of the following statements about covalent and ionic bonds is correct?

Accepted Answer

Covalent bonds are generally stronger than ionic bonds in biological systems.

Chapter 2: The Chemical Basis of Life – Study Notes

Study Guide - Practice Questions