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Essential Chemistry for IGCSE - Particles And Purification (Section 5)

1
When a gas is compressed in a container, which of the following is likely to occur?
Answer
(A)
The volume of the gas decreases and the pressure increases.
2
What do you need to be able to measure when you want to determine the density of a solid, such as a rock?
Answer
(C)
mass and volume
3
Which of the following describes the change from a gas to a solid?
Answer
(C)
Deposition
4
What type of separation method is used to separate different dyes in ink?
Answer
(C)
Chromatography
5
If you put a drop of food coloring into water, which process will cause the color to spread throughout the water?
Answer
(B)
Diffusion
6
What is a common way to determine if a substance is chemically pure?
Answer
A
C
D
7
Which state of matter has the strongest forces of attraction between its particles?
Answer
(C)
Solid
8
What type of energy is directly associated with the temperature of a substance?
Answer
(B)
Kinetic Energy
9
What are the steps involved in a typical paper chromatography experiment?
Answer
A
B
C
D
10
What type of apparatus is used in filtration?
Answer
(D)
A filter funnel.
11
Which of the following describes the movement of particles in Brownian motion?
Answer
(B)
Random, erratic.
12
Which state of matter has the lowest density under normal conditions?
Answer
(C)
Gas
13
Which of the following best describes the motion of particles in a solid?
Answer
(B)
They vibrate in fixed positions.
14
What does the term “pure substance” mean in the context of chemistry?
Answer
(A)
A substance with no impurities.
15
Which property is always conserved during a physical change?
Answer
(A)
Mass
16
Which of these is often the best method for separating ethanol and water?
Answer
(C)
Fractional distillation
17
What is the relationship between the average kinetic energy and the temperature of a substance?
Answer
(A)
They are directly proportional.
18
What does the term 'diffusion' describe?
Answer
(A)
The movement of particles from a region of high concentration to a region of low concentration.
19
What property of the substances allows their separation in paper chromatography?
Answer
(C)
Solubility and attraction to the paper.
20
What is Brownian motion?
Answer
(B)
The random movement of particles suspended in a liquid or gas.
21
What is a common impurity that can affect the purity of a substance?
Answer
(A)
Another substance
22
What is the best way to describe the arrangement of particles in a gas?
Answer
(C)
Far apart, random arrangement
23
Which of the following is the solid left on the filter paper after filtration?
Answer
(B)
Residue
24
What happens to the particles in a substance at its freezing point?
Answer
(A)
The particles lose energy and begin to move in fixed positions.
25
What will happen if you add more solute to a saturated solution?
Answer
(B)
The solute will not dissolve.
26
What happens to the particles of a solid when it melts?
Answer
(D)
They begin to move further apart and can slide past each other.
27
Which of these is not a method of separating a mixture?
Answer
(D)
Dissolving
28
Which of the following methods involve evaporation?
Answer
A
B
29
Which of the following statement(s) is/are true about a pure substance?
Answer
A
B
30
Which of the following are considered to be impurities?
Answer
A
C
31
What is the purpose of a fractionating column in fractional distillation?
Answer
(B)
To increase the surface area for condensation and re-evaporation.
32
What is the name of the liquid that is collected during the distillation process?
Answer
(C)
Distillate
33
What is the main purpose of separating a mixture?
Answer
(C)
To obtain the individual components.
34
What is the meaning of the term "purity" in chemistry?
Answer
(B)
The substance only contains one type of molecule.
35
What instrument is used to measure mass?
Answer
(B)
Balance
36
Which technique is most suitable for separating a mixture of sand and iron filings?
Answer
(C)
Using a magnet
37
What is the stationary phase used in paper chromatography?
Answer
(B)
The filter paper
38
What happens to the melting point of a substance when it has impurities?
Answer
(C)
It decreases.
39
Which change of state is the reverse of condensation?
Answer
(C)
Evaporation
40
What happens to the particles of a substance as it changes from a liquid to a gas (evaporation)?
Answer
(B)
They gain energy and move faster.
41
What happens to the temperature of a substance during a phase change (e.g., melting or boiling)?
Answer
(C)
The temperature remains constant.
42
What must a student remember when taking volume readings?
Answer
(B)
Read from eye level with the meniscus.
43
Which of the following will *decrease* the melting point of a pure substance?
Answer
(C)
The presence of an impurity.
44
Which of the following methods can be used to determine a substance's purity?
Answer
A
B
C
45
What happens to the pressure of a gas when its volume decreases at a constant temperature?
Answer
(A)
The pressure increases.
46
What is the purpose of the beaker in the paper chromatography setup?
Answer
(A)
To act as a solvent reservoir
47
Which of the following factors influences the rate of migration of a dye in paper chromatography?
Answer
A
B
C
48
What is a key characteristic of a pure substance during melting?
Answer
(B)
Melting at a specific, sharp temperature.
49
Which method is suitable for separating a mixture of two miscible liquids?
Answer
(C)
Distillation
50
Which technique is best used to separate two miscible liquids with very different boiling points?
Answer
(A)
Simple distillation