Chapter 9 review
Answer Section
MODIFIED TRUE/FALSE
1. ANS: T
2. ANS: F
When a solution of salt in water is distilled, both the salt AND the water are collected.
3. ANS: T
4. ANS: T
5. ANS: T
6. ANS: T
7. ANS: F
Flotation is a type of mechanical sorting that depends on density.
8. 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.
9. ANS: F
The best way to separate sand from gravel would be sifting or filtration.
10. ANS: F
Filtration can be used to separate a solid from a liquid or a gas component (e.g. sawdust from air).
11. ANS: T
12. ANS: T
13. ANS: T
14. ANS: F
Paper chromatography is best used to separate homogeneous liquid mixtures (solutions).
COMPLETION
15. ANS:
evaporation
(The solutes remain on the paper; the solvents evaporate into the air.)
16. ANS: temperature
17. ANS: low boiling point
18. ANS: condensation
19. ANS: paper chromatography
20. ANS: magnetism
21. ANS: Paper chromatography
22. ANS: evaporation
23. ANS:
screening
filtration
MATCHING
24.
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28.
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30.
31.
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35.
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38.
39.
ANS:
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ANS:
E
A
D
B
C
D
B
C
A
E
B
G
D
C
H
A
SHORT ANSWER
40. ANS:
Student answers may vary. Possible answers include:
Filtration. Example: filtered coffee.
Settling. Example: settling of muddy water
41. ANS:
a) Water undergoes evaporation at A; particles suddenly become much farther apart.
b) Only water particles in the gas state are found at point B.
c) At point D, water particles cool and cling together. This is called condensation.
d) Clear water collects at E; mud and silt collects at A.
42. ANS:
A pit has been dug in the moist soil, and a bowl placed at the bottom. A sheet of plastic is stretched
over the pit, held in place by stones. One stone is placed on the centre of the sheet. When solar
energy heats the pit, water evaporates from the soil. The water condenses on the cooler plastic and
runs downward toward the centre, where it falls into the bowl. This is an example of separation by
distillation: the dirt is left behind, and the water is recovered.
ESSAY
43. ANS:
Student answers should be similar to the following: All matter is made up of extremely tiny
particles. Pure salt and pure water each have their own kind of particle, different from all other
particles. When salt is stirred with water, the attractive forces between the salt particles and water
particles are stronger than those between individual salt particles, so the water particles surround the
salt particles, forming a homogeneous mixture. Solutions are separated based on the properties of the
particles that are in the solution. For example, water is easily vaporized at 90°C, but salt is not. As
the solution is heated to 90°C, the attractive forces between the salt particles and the water particles
are weakened, allowing the water to evaporate, while the salt particles remain attracted to each other
in the solid state.
44. ANS:
Students should begin with the
classification-of-matter chart. If the
matter is a pure substance, such as
sugar, no separation is necessary. If the
matter is a mixture, the method of
separation will depend on whether the
mixture is a solution or another type of
mixture. Solutions, such as sugar water,
can be separated using evaporation,
distillation and/or chromatography.
Other mixtures, such as sand and
leaves, can be separated by settling,
sieving, filtration or flotation.