2- Unit review exercises

Question 1

What change in the physical state occurs when sufficient heat is applied to a liquid?

a. Dissolves.
b. Contracts.
c. Turns to gas.
d. Becomes a solid.

Answer 1

Turns to gas

Question 2

Which of the physical states of matter lacks both volume and shape?

a. Solid and liquid.
b. Gas and liquid.
c. Liquid only.
d. Gas only.

Answer 2

Gas only.

Question 3

If matter is uniform in composition and properties then it is considered to be

a. heterogeneous.
b. homogeneous.
c. covalent.
d. binary.

Answer 3

homogeneous

Question 4

Which example best describes a solution?
a. Methane gas combined with carbon dioxide gas.
b. Ethyl alcohol dissolved in water.
c. Beaker of sodium hydroxide.
d. Container of argon gas.

Answer 4

Ethyl alcohol dissolved in water

Question 5

The number of protons in the nucleus of an atom is equal to the
a. electron number.
b. electron weight.
c. atomic number.
d. atomic weight.

Answer 5

atomic number

Question 6

The mass number of an atom is equal to the sum of the number of

a. neutrons, electrons and protons.
b. neutrons and electrons.
c. protons and electrons.
d. protons and neutrons.

Answer 6

protons and neutrons

Question 7

Where are the noble gases located within the periodic table?

a. Far right column.
b. Far left column.
c. Bottom row.
d. Top row.

Answer 7

Far right column

Question 8

Due to their high reactivity, what commonly combines with organic compounds to form
dangerous chemicals that can be toxic to humans?

a. Metals.
b. Alkalis.
c. Halogens.
d. Noble gases.

Answer 8

Halogens

Question 9

Elements form compounds in an attempt to

a. become more stable.
b. disperse energy.
c. become inert.
d. gain energy.

Answer 9

become more stable.

Question 10

A cation has a positive charge because the atom has
a. more neutrons than protons.
b. fewer neutrons than protons.
c. more protons than electrons.
d. fewer protons than electrons.

Answer 10

more protons than electrons

Question 11

(009) It is important to understand the chemical relationships that place compounds into distinct
groups so you can more easily determine the
a. percent by mass of the compounds.
b. saturation rate of the compounds.
c. concentration of the compounds.
d. hazards of the compounds.

Answer 11

hazards of the compounds

Question 12

If 50 grams of sodium chloride dissolves in enough water to make 500 grams of solution,
what is the percent by mass?

Answer 12

10 percent

Question 13

What type of solution contains large amounts of both a weak acid and its conjugate base so
that it resists change in its potential of hydrogen (pH) level?

a. Buffer.
b. Alkaline.
c. Neutral.
d. Acidic.

Answer 13

Buffer

Question 13

A solution with a potential of hydrogen (pH) of 3 is considered
a. buffered.
b. alkaline.
c. neutral.
d. acidic.

Answer 13

acidic

Question 14

What is the molecular weight of a substance based on one mole?
a. 6.022 x 1021.
b. 6.022 x 1022.
c. 6.022 x 1023.
d. 6.022 x 1024.

Answer 14

6.022 x 1023

Question 15

Gay-Lussac’s law states that at a constant volume the pressure of a fixed mass of a given
gas is directly proportional to the temperature (in Kelvin); therefore, as pressure
a. decreases, temperature increases.
b. increases, temperature increases.
c. decreases, temperature remains constant.
d. increases, temperature remains constant.

Answer 15

b. increases, temperature increases