Unit Test — Unit test Answers

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Which statement describes an extensive property of matter?

A
It changes with the color of a substance.
B
It changes when a new substance is formed.
C
It changes with the amount of sample that is present.
D
It changes with the composition of a substance.
3

Which of these factors will cause a solid solute to dissolve faster?

A
increasing the air temperature
B
increasing the amount of solute
C
increasing the amount of solvent
D
increasing the surface area of solute
4

Which statement describes a chemical property of water?

A
It reacts with sodium metal.
B
It has a melting point of 0°C.
C
It has a density of about 1 g/mL.
D
It is clear and colorless.
5

Which of these is an example of a physical change?

A
sugar, when heated, producing carbon dioxide and water
B
solid ice, when heated, turning into liquid water
C
sodium, when exposed to chlorine, forming sodium chloride
D
aluminum, when heated in air, forming aluminum oxide
6

When a strip of magnesium metal is touched to a flame, a bright light and a whitish substance are produced. Why is the burning of magnesium considered a chemical change?

A
because the metal reaches a high temperature
B
because the metal begins to melt
C
because a new substance is formed
D
because the metal is malleable
7

Which of the following observations would indicate that a material is a pure substance?

A
It does not dissolve in water.
B
It changes color after heating.
C
It cannot be physically broken down into different types of atoms.
D
It can be physically broken down into different types of molecules.
8

best

a
a colloid
a
a suspension
a
a solution
a
an alloy
10

A piece of sodium metal can be described as

A
a pure substance and a compound.
B
an impure substance that is reactive.
C
an impure substance that is unreactive.
D
a pure substance and an element.
11

Which is an example of a nonaqueous solution?

A
gasoline
B
fog
C
mayonnaise
D
fruit juice
13

Which statement describes heterogeneous mixtures?

A
They are made up of two or more pure substances that are not chemically bonded together and appear non-uniform.
B
The substances they are composed of can only be separated chemically.
C
The substances they are composed of have fixed ratios between their components.
D
They are made up of two or more pure substances that are chemically bonded together and appear uniform.
14

Which statement accurately describes part of the dissolving process of a polar solute in water?

A
Solute molecules repel water molecules.
B
Water molecules surround solute molecules.
C
Water molecules are strongly attracted to nonpolar substances.
D
Solute molecules remain concentrated in one part of the solvent.
15

Which factor influences both solubility and the rate of dissolution?

A
pressure
B
temperature
C
particle size
D
nature of solvent

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