$$\text{Number of neutrons} = \text{Mass number} - \text{Atomic number}$$

Question 1

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

Accepted Answer

An element consists of only one type of atom, while a compound consists of two or more different elements chemically bonded together.

Question 2

A neutral atom of carbon has an atomic number of 6 and a mass number of 14. How many neutrons does it have?

Accepted Answer

8

Question 3

Which of the following bonds is primarily responsible for the unique properties of water, such as cohesion and high specific heat?

Accepted Answer

Hydrogen bonds

Question 4

If the pH of a solution changes from 7 to 4, how does the concentration of hydrogen ions $$[H^+]$$ change?

Accepted Answer

It increases by a factor of $$10^3$$

Question 5

Which statement correctly distinguishes between isotopes of the same element?

Accepted Answer

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

Question 6

A sodium atom ($$Na) $$has an atomic number of 11. How many electrons are in its outer (valence) shell?

Accepted Answer

1

Question 7

Which of the following best explains why water is an excellent solvent for ionic compounds?

Accepted Answer

Water molecules are polar and can form hydration shells around ions.

Question 8

When water dissociates, which ions are produced?

Accepted Answer

$$OH^-$$ and $$H^+$$

Question 9

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

Accepted Answer

Cohesion

Question 10

A buffer in blood helps maintain pH by:

Accepted Answer

Absorbing excess $$H^+ or$$ $$OH^-$$ ions to minimize pH changes.

Question 11

Which of the following substances is most likely to be hydrophobic?

Accepted Answer

Vegetable oil

Question 12

Which scenario best illustrates adhesion?

Accepted Answer

Water droplets sticking to a spider web after rain.

Question 13

If you know the atomic number and mass number of an atom, which formula allows you to calculate the number of neutrons?

Accepted Answer

$$	ext{Number of neutrons} = 	ext{Mass number} - 	ext{Atomic number}$$

Question 14

Which of the following is a real-world example of water's high specific heat capacity?

Accepted Answer

Large lakes moderating the climate of nearby land.

Question 15

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

Accepted Answer

Covalent bond

Question 16

A solution is made by dissolving $$10$$ grams of sugar in $$100 mL of $$water. In this scenario, which is the solute?

Accepted Answer

Sugar

Question 17

Which of the following best describes an ion?

Accepted Answer

An atom with a different number of protons and electrons.

Question 18

Which of the following statements about acids and bases is correct?

Accepted Answer

Bases increase the concentration of $$OH^-$$ ions in solution.

Question 19

A patient’s blood pH drops from 7.4 to 7.1. By what factor has the $$[H^+]$$ concentration increased?

Accepted Answer

By a factor of $$10^0.3$$ \approx 2$$

Question 20

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

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds hold water molecules further apart in the solid state.

Chapter 2: Chemistry – Study Guide and Key Concepts for General Biology

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