Essential Chemistry for IGCSE - Particles And Purification (Section 2)
1
In a heating curve, what does a horizontal section represent?
Answer
(B)
A change in state.
2
Which method is commonly used to separate a solid from a liquid?
Answer
(A)
Filtration
3
What is the purpose of the baseline in paper chromatography?
Answer
(B)
To mark where the sample is spotted
4
What is the solid remaining on the filter paper called after filtration?
Answer
(B)
Residue
5
In paper chromatography, what is used as the mobile phase?
Answer
(C)
A suitable solvent
6
If a substance has impurities, what would happen to its melting point?
Answer
(C)
It will decrease.
7
In a closed container, how does the pressure of a gas change if the number of gas molecules is increased, while keeping the volume and temperature constant?
Answer
(A)
Pressure increases.
8
Which of the following is an example of a chemical change?
Answer
(C)
Rusting of iron
9
What is the role of the mobile phase in chromatography?
Answer
(B)
To carry the sample through the stationary phase.
10
What is a suspension?
Answer
(B)
A heterogeneous mixture where particles are temporarily suspended.
11
What happens to the space between particles as a substance changes from a solid to a liquid?
Answer
(A)
The space between particles increases.
12
Which of the following are important for a successful chromatography experiment?
Answer
A
C
13
Which of these is NOT a unit for measuring volume?
Answer
(C)
kg
14
What happens to the average kinetic energy of the particles in a substance as the temperature increases?
Answer
(B)
Increases
15
Which instrument should be used to measure the volume of an irregular solid object?
Answer
(D)
A displacement can
16
In a heating curve, the flat parts represent what?
Answer
(B)
A phase change.
17
What does the 'concentration gradient' refer to in the process of diffusion?
Answer
(B)
The difference in concentration between two areas.
18
Which of the following phase changes require energy to be absorbed by the substance?
Answer
A
C
19
How does the mass of the solute affect the rate of diffusion?
Answer
(B)
Heavier solute molecules diffuse slower.
20
Which of the following is a suitable method to separate a solid from a liquid?
Answer
(C)
Filtration
21
What is the definition of temperature in relation to the kinetic particle theory?
Answer
(B)
The average kinetic energy of the particles.
22
How can the rate of diffusion be increased?
Answer
A
B
23
What are the characteristic of a pure substance?
Answer
A
B
24
Which of the following is most appropriate for separating a mixture of salt and water?
Answer
(B)
Distillation
25
Which of the following is the best method to separate ethanol from water?
Answer
(C)
Fractional distillation
26
Which of the following will cause an increase in the pressure of a gas inside a closed container?
Answer
A
B
C
27
What is the scientific definition of pressure?
Answer
(A)
The amount of force exerted per unit area.
28
In paper chromatography, what is the role of the solvent front?
Answer
(C)
To determine the R_f value
29
What is the main difference between simple distillation and fractional distillation?
Answer
(C)
Fractional distillation separates liquids with different boiling points, while simple distillation is for liquids with significantly different boiling points.
30
Which statement accurately describes the behavior of gas particles?
Answer
(C)
They move randomly and collide with each other and the container walls.
31
Which of these techniques is used to separate amino acids?
Answer
(B)
Paper chromatography
32
What process is used to separate a solid from a liquid by allowing it to form crystals?
Answer
(C)
Crystallization
33
Which is used to separate a solid dissolved in a liquid?
Answer
(B)
Simple distillation
34
What is the difference between a pure substance and a mixture?
Answer
(B)
A pure substance is made of one type of substance, and mixtures are not.
35
Which of the following describes the process of condensation?
Answer
(C)
A gas changing to a liquid
36
What does the term "saturated solution" mean?
Answer
(A)
A solution that is not able to dissolve any more solute at a given temperature.
37
Which factors can be used to identify an unknown substance?
Answer
A
B
C
38
What is a solute?
Answer
(B)
The substance that is dissolved
39
In chromatography, what is the mobile phase?
Answer
(B)
The solvent
40
What is the correct definition of a solvent?
Answer
(A)
The substance that dissolves in another substance
41
What is the main goal of purifying a substance?
Answer
(B)
To remove unwanted components.
42
Which of the following statements about diffusion is correct?
Answer
(C)
Diffusion occurs due to the random movement of particles.
43
Which of the following correctly describes the arrangement of particles in a liquid?
Answer
(B)
Random arrangement, closely packed, move around each other.
44
What happens to the rate of diffusion if the temperature is decreased?
Answer
(B)
The rate of diffusion decreases
45
Which state of matter takes the shape of its container but has a fixed volume?
Answer
(B)
Liquid
46
Which of the following are used to measure volume?
Answer
A
C
47
Which state of matter is most easily compressed?
Answer
(C)
Gas
48
Which of the following can be accurately measured using a burette?
Answer
(A)
The volume of acid used in a titration.
49
According to the kinetic particle theory, which of the following is true about particles in a gas?
Answer
(C)
They move randomly and are far apart.
50
Which of the following can be used to accurately measure the volume of a gas?
