Grade 7
Unit 3 Test Review
Name: _______________________
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the
statement true.
____
1. You shine a light through a liquid, but you cannot see the beam as it passes through. The liquid must
be a heterogeneous mixture.
_____________________________________________________________________
____
2. Mixtures that have two or more visible parts with distinct sets of properties are heterogeneous.
_____________________________________________________________________
____
3. Both solutions and mixtures have more than one type of matter.
_____________________________________________________________________
____
4. Apple juice is a heterogeneous mixture.
_____________________________________________________________________
____
5. Homogeneous mixtures can be found in the solid state, the liquid state, and the gas state.
_____________________________________________________________________
____
6. A stainless steel fork is a solution.
_____________________________________________________________________
____
7. Sugar water is an example of a heterogeneous mixture.
_____________________________________________________________________
____
8. A concentrated solution contains a low mass of solute for a certain volume of solvent.
_____________________________________________________________
____
9. As water evaporates from a solution of salt and water, the concentration of salt decreases.
_____________________________________________________________________
____ 10. A solute dissolves more slowly when the mixture is stirred.
_____________________________________________________________________
____ 11. The attraction between sugar and water particles in a solution of sugar and water is weaker than the
attraction between sugar and sugar particles in solid sugar.
_____________________________________________________________________
____ 12. The size of sugar pieces does not affect the rate at which the sugar dissolves in water.
_____________________________________________________________________
____ 13. Breaking a solute into smaller pieces makes it dissolve faster because the particles move faster.
_____________________________________________________________________
____ 14. One cup of salt was added to a plastic bottle of pure water, and sealed. One year later, some salt
could still be visible on the bottom of the bottle. This is an example of an unsaturated solution.
_____________________________________________________________________
____ 15. At higher water temperatures, the solubility of sugar decreases, but the solubility of carbon dioxide
increases.
_____________________________________________________________________
____ 16. When a solution of salt in water is distilled, only the salt is collected.
_____________________________________________________________________
____ 17. In the process of distillation, both evaporation and condensation take place.
_____________________________________________________________________
____ 18. Distillation is a method for separating matter that depends on differences in boiling points.
_____________________________________________________________________
____ 19. Paper chromatography uses the property of absorption to separate mixtures.
_____________________________________________________________________
____ 20. When gold is refined, chemicals are added that are able to dissolve the gold, but cannot dissolve the
rock.
_____________________________________________________________________
____ 21. Crude oil is a mixture of many pure substances that can be separated in a fractionating tower.
_____________________________________________________________________
____ 22. Flotation is a type of mechanical sorting that depends on particle size.
_____________________________________________________________________
____ 23. Using a filter, you can separate the parts of a homogeneous mixture more effectively than the parts of
a heterogeneous mixture.
Completion
Complete each statement.
24. Mixtures can be heterogeneous or ____________________.
25. A solution of metals is a(n) ____________________ .
26. Carbonated water is an example of a solution of a liquid and a(n) ____________________.
27. A substance that contains only one kind of particle is referred to as a(n)
________________________.
28. The element copper is an example of a(n) ____________________ substance.
29. A homogeneous mixture is also known as a(n) _______________.
30. When vinegar and oil are shaken together, they form a cloudy substance that gradually separates into
oil and vinegar again. This is an example of a(n) ____________________________.
31. In a solution of carbon dioxide and water, the water is the _______________________ and the
carbon dioxide is the _______________________.
32. Fog will scatter a light beam. Fog is an example of a ___________________ mixture.
33. The substance in which a solute dissolves is called the ____________________.
34. Usually, to make a dilute solution, you would dissolve a ___________ quantity of solute in a
__________ quantity of solvent.
35. If you have a concentrated solution, you can make a dilute solution by adding more
____________________.
36. When a saturated solution of sugar in water is gently heated, it will become ______________.
37. Fog is best described as a _____________________________ of water in air.
38. When you open a bottle of soda water, bubbles of carbon dioxide “fizz” appear. The
_____________ of dissolved carbon dioxide is decreasing.
39. After you mark on a piece of paper with a marker pen, the liquid components of the ink are separated
by the method of ______________________.
40. A mixture consists of sand grains and iron grains of about the same size. They could be separated by
______________.
41. ___________________________ can be used to separate the coloured substances in a mixture.
42. A naturally occurring process that separates a solid solute from a liquid solvent is the process of
_____________.
43. Gravel consists of sand, pebbles, and stones of various sizes. This mixture can be separated by the
method of _________________.
Short Answer
44. Brass is a homogeneous mixture made up of about one third zinc and two thirds copper. What is the
solute and what is the solvent in this solution?
45. Examine the solubility curves in the graph below. In one sentence each, state the solubility of each
solute at 20°C.
46.
Explain the difference between a heterogeneous and a homogeneous mixture and give two
examples of each.
47. Define the following terms:
- solute
- solvent
- solubility
- concentrated solution
- dilute solution
48. Give an example of concentration expressed quantitatively and qualitatively.
49. Use the PTM to explain why some substances dissolve in a solvent and others do not.
Grade 7 Unit 3 test review
Answer Section
MODIFIED TRUE/FALSE
1. ANS:
F
The liquid must be a solution.
2. ANS:
T
3. ANS:
T
4. ANS:
T
5. ANS:
T
6. ANS:
T
PTS
7. ANS:
F
Sugar water is an example of a homogeneous mixture, that
is, a solution.
8. ANS:
F
A concentrated solution contains a high mass of solute for a
certain volume of solvent.
9. ANS:
F
As water evaporates from a solution of salt and water, the
concentration of salt increases.
10. ANS:
F
A solute dissolves more quickly when the mixture is stirred.
11. ANS:
F
The attraction between sugar and water particles is stronger
than the attraction between sugar and sugar particles;
otherwise, the sugar would not dissolve as readily as it does.
12. ANS:
F
The size of sugar pieces affects the rate at which sugar
dissolves in water. One gram of sugar broken into smaller
pieces dissolves faster than larger clumps of sugar because
the small pieces present a larger surface area to the water.
13. ANS:
F
Breaking a solute into smaller pieces makes it dissolve
faster because the surface of the solute is increased.
14. ANS:
F
This is an example of a saturated solution, since the salt has
not dissolved.
15. ANS:
F
At higher water temperatures, the solubility of sugar
increases (we heat honey to soften it by dissolving the
sugar), but the solubility of carbon dioxide decreases.
(Think of warm ginger ale.)
16. ANS:
F
When a solution of salt in water is distilled, both the salt
AND the water are collected.
17. ANS:
T
18. ANS:
T
19. ANS:
T
20. ANS:
T
21. ANS:
T
22. ANS:
F
Flotation is a type of mechanical sorting that depends on
density.
23. ANS:
F
Using a filter, you cannot separate the parts of a
homogeneous mixture (the particles of the mixture are too
small), but you can separate the parts of a heterogeneous
mixture.
COMPLETION
24. ANS:
homogeneous
25. ANS:
alloy
26. ANS:
gas
27. ANS:
pure substance
28. ANS:
pure
29. ANS:
solution
30. ANS:
heterogeneous mixture
31. ANS:
solvent, solute
32. ANS:
heterogeneous
33. ANS:
solvent
34. ANS:
small, large
35. ANS:
solvent
36. ANS:
unsaturated
37. ANS:
heterogeneous solution
38. ANS:
solubility; concentration (solubility is max
concentration, at fixed temperature)
39. ANS:
evaporation
(The solutes remain on the paper; the solvents evaporate
into the air.)
40. ANS:
magnetism
41. ANS:
Paper chromatography
42. ANS:
evaporation
43. ANS:
screening
filtration
Answer Key – Unit Three Review – Constructed Response
Questions
44. Solute – zinc. Solvent - copper
45. Potassium Chlorate – 20 g/100g or 200g/Kg
Sodium Chloride – 39g/100L or 390g/Kg
Ammonia – 25g/L or 250g/Kg
46. Heterogeneous mixture – a mixture where you can
see the individual parts, these mixtures are separated
by mechanical sorting. Example: chocolate chip
cookie, salad
Homogeneous mixture – a mixture where you can not
see the different parts so it appears as one substance,
they are separated by evaporation and distillation.
Example: tap water, antifreeze
47. Solute - the substance present in the lesser amount
and the part that dissolves in the solvent.
Solvent – the substance present in the greater amount
and the part that the solute dissolves in.
Solubility – the ability for a substance to dissolve in
another substance.
Concentrated solution – a solution that has a lot of
solute for a certain amount of solvent.
Dilute solution – a solution that has a small amount of
solute for a certain amount of solvent.
48. Quantitative – uses numbers to describe a scientific
concept, Example: the concentration of a solution is
6g /L
Qualitative – uses words to describe a scientific
concept, Example: the solution is very concentrated.
49. For a solute to dissolve will dissolve in a solvent the
solute particles must be more strongly attracted the
particles of the solvent than to themselves.