Mrs. Lee – 8th grade Physical Science
Page 1
Ch 7 Practice Test – Answer Key
______ c
1) A solution is an example of a ______.
a) homogeneous colloid
b) heterogeneous colloid
c) homogeneous mixture
d) heterogeneous mixture
______ b
2) Magnesium sulfide and aluminum fluoride are ______.
a) ionic compounds
b) molecular compounds
c) covalent electrons
d) radioactive elements
______ a
3) When dissolved in water, ionic compounds ______.
a) conduct electricity
b) make the water cloudy
c) forms double and triple bonds
d) do not conduct electricity
______ d
4) When dissolved in water, molecular compounds ______.
a) conduct electricity
b) make the water cloudy
c) form double and triple bonds
d) do not conduct electricity
______ a
5) A mixture in which particles can be seen and easily separated by settling or
filtration is a ______.
a) suspension
b) solution
c) solute
d) solvent
______ b
6) A neutral solution has a pH of ______.
a) 3 b) 7 c) 5 d) 9
______ c
7) A base ______.
a) tastes sour
c) does not react with carbonates
b) corrodes metals
d) turns litmus red
______ c
8) Solutes lower the freezing point of water by ______.
a) stopping water molecules from moving
b) forming crystals
c) making it harder for water to form crystal
d) making the water molecules move faster
______ b
9) A polar solvent will most likely dissolve ______.
a) any solute
b) polar solutes
c) nonpolar solutes
d) no solute
______ c
10) If you add a small amount of hydrochloric acid to 4 liters of water, what type
of solution would you expect to have?
a) concentrated solution
b) basic solution
c) dilute solution
d) saturated solution
______ d
11) The pH scale ______.
a) is numbered from 1 to 12
b) measures the concentration of bases
c) measures the concentration of acids
d) measures the concentration of hydrogen ions
Ch 7 Practice Test – Answer Key
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Mrs. Lee – 8th grade Physical Science
Page 2
Ch 7 Practice Test – Answer Key
______ a
12) Neutralization ______.
a) is a reaction between an acid and a base
b) occurs when acid is dissolved in water
c) forms an acid and a base
d) does not change the pH of a solution
______ c
13) Ammonia (NH3) reacts with water to form hydroxide ions. The resulting
solution ______.
a) turns blue litmus paper red
b) causes red litmus paper to remain red
c) turns red litmus paper blue
______ b (concentrated)
14) If you add solute to a dilute solution, the solution becomes a
more dilute solution.
a) True
b) False
______ a
15) Acids are described as being corrosive, because they dissolve some metals.
a) True
b) False
______ b (indicator) 16) A suspension is a substance that turns different colors in an acid or a
base.
a) True
b) False
______ b (colloid) 17) A salt is a mixture containing small, undissolved particles that do not
settle out.
a) True
b) False
______ a
18) When a base reacts with an acid, water and a salt form.
a) True
b) False
______ a
19) When acids react with carbonate compounds, carbon dioxide forms.
a) True
b) False
______ b (acid)
20) A base forms hydrogen ions when it dissolves in water.
a) True
b) False
______ b (solvent) 21) The solute is the part of a solution present in the largest amount.
a) True
b) False
______ b (increase) 22) Solutes decrease the boiling point of a solvent.
a) True
b) False
______ c
23) A mixture in which particles can be seen and easily separated is a ______.
a) solution
b) solvent
c) suspension
Ch 7 Practice Test – Answer Key
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Mrs. Lee – 8th grade Physical Science
Page 3
Ch 7 Practice Test – Answer Key
______ c
24) Solutes lower the freezing point of water by ______.
a) making the water molecules move faster
b) forming salts
c) making it harder for water molecules to form crystals
______ a
25) Which is a dilute solution?
a) 1 gram of salt dissolved in 100 grams of water
b) 100 grams of salt dissolved in 100 grams of water
c) 150 grams of salt dissolved in 100 grams of water
______ a
26) At higher pressure ______.
a) more gas can dissolve
b) less gas can dissolve
c) gases cannot dissolve at all
______ c
27) An acid ______.
a) tastes bitter
b) turns red litmus paper blue
c) dissolves some metals
______ b
28) Both sodium hydroxide (NaOH) and potassium hydroxide (KOH) produce
hydroxide ions (OH-) in water. These compounds are ______.
a) acids
b) bases
c) salts
______ c
29) The pH scale ______.
a) is numbered from 1 to 12
b) measures the concentration of salts
c) measures the concentration of hydrogen ions (H+)
______ b
30) Neutralization ______.
a) forms an acid and a base
b) is a reaction between an acid and a base
c) occurs when an acid dissolves in water
______ b
31) Which factor is least likely to affect solubility?
a) pressure
b) volume
c) temperature
______ c
32) A solid that produces H+ ions when dissolved in water will create a solution
that has ______.
a) a neutral pH
b) a pH higher than neutral c) a pH lower than neutral
______ a
33) A mixture containing small, undissolved particles that do not settle out is a
colloid.
a) True
b) False
______ a
34) If you add solute to a dilute solution, the solution becomes a more
concentrated solution.
a) True
b) False
Ch 7 Practice Test – Answer Key
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Mrs. Lee – 8th grade Physical Science
Page 4
Ch 7 Practice Test – Answer Key
______ a
35) A solution that contains more solute than predicted at a given temperature is
supersaturated.
a) True
b) False
______ b
36) The solute is the largest part of a solution.
a) True
b) False
______ a
37) Solubility can be used to identify an unknown substance.
a) True
b) False
______ a
38) A base tastes bitter, feels slippery, and turns red litmus paper blue.
a) True
b) False
______ b
39) A base forms hydrogen ions when it dissolves in water.
a) True
b) False
______ b
40) A cook would never use an acid when baking a cake.
a) True
b) False
Use the picture below to answer the following 2 questions:
______ b
41) Inferring: The jar in the diagram has been shaken up, then allowed to sit for
a day. What kind of solution is this?
a) dilute solution
b) saturated solution
c) unsaturated solution
______ c
42) Applying Concepts: To change this solution to a supersaturated solution,
you would have to ______.
a) add more water
b) add more sugar
c) heat the solution
Use the equation below to answer the following 3 questions:
NH3 + H2O  NH4+ + OH-
Ch 7 Practice Test – Answer Key
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Mrs. Lee – 8th grade Physical Science
Page 5
Ch 7 Practice Test – Answer Key
______ b
43) Interpreting Diagrams: This equation shows what happens when ammonia
(NH3) dissolves in water (H2O). From this, you can tell that ammonia is a(n)
______.
a) acid
b) base
c) salt
______ a
44) Applying Concepts: What would be the pH of the solution formed when
ammonia (NH3) dissolves in water?
a) greater than 7
b) equal to 7
c) less than 7
______ a
45) Applying Concepts: The solution formed when ammonia (NH3) dissolves in
water can conduct electricity because _____.
a) it contains ions
b) it contains molecules
c) it contains table salt
Ch 7 Practice Test – Answer Key
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