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Essential Chemistry for IGCSE - Particles And Purification (Section 4)

1
What is the purpose of a centrifuge in a separation process?
Answer
(C)
To spin the solution at high speed to separate solid from liquid.
2
Which of the following statements is correct regarding melting and boiling points?
Answer
(D)
Impurities broaden the melting range and can lower melting and increase boiling point.
3
Which property is primarily utilized in the method of distillation?
Answer
(C)
Boiling point
4
If you heat a liquid in a closed container, what happens to the pressure inside?
Answer
(A)
Pressure increases.
5
Which process separates liquids based on their boiling points?
Answer
(C)
Distillation
6
What does Brownian motion provide evidence for?
Answer
(B)
The random movement of particles in fluids.
7
What can you measure using a gas syringe?
Answer
(C)
The volume of a gas.
8
What happens to the boiling point of a liquid when it is impure?
Answer
(D)
The boiling point becomes inconsistent.
9
Which of the following is the process where a gas turns into a liquid?
Answer
(C)
Condensation
10
What process would you observe to see Brownian motion?
Answer
(B)
Observing smoke particles in a glass box
11
Which of the following factors affects the rate of diffusion?
Answer
A
B
C
12
In a laboratory, what tool is used to measure accurate temperature?
Answer
(C)
A thermometer
13
Which of the following methods can be used to purify a substance?
Answer
A
B
D
14
Which technique is best for separating two liquids with significantly different boiling points?
Answer
(B)
Simple distillation
15
What is the name of the liquid that passes through the filter paper in filtration?
Answer
(B)
Filtrate
16
During melting, what happens to the energy absorbed by the substance?
Answer
(B)
It increases the potential energy, breaking intermolecular bonds.
17
How does increasing the concentration gradient affect the rate of diffusion?
Answer
(B)
It increases the rate of diffusion.
18
What type of mixtures can be separated by fractional distillation?
Answer
(B)
Mixtures of liquids with similar boiling points.
19
What technique is used to separate components of a solution based on their different solubilities in a solvent?
Answer
(B)
Chromatography
20
If a substance is heated and changes state, what will happen to its mass?
Answer
(C)
Mass stays the same
21
What would happen if the sample spot was placed below the solvent level in paper chromatography?
Answer
(C)
The sample will dissolve into the solvent, and the separation cannot occur.
22
Which of the following is an example of diffusion?
Answer
(B)
Sugar dissolving in water.
23
What is the name of the apparatus used to accurately measure the volume of a liquid?
Answer
(C)
Measuring cylinder
24
In paper chromatography, which way does the solvent usually travel?
Answer
(B)
Vertically up the paper
25
What is the relationship between temperature and the rate of diffusion?
Answer
(D)
As temperature increases, the rate of diffusion increases.
26
Which type of distillation is best suited for separating ethanol and water?
Answer
(B)
Fractional distillation
27
Which of the following statements are TRUE about diffusion?
Answer
B
C
28
What happens to the pressure of a gas if you decrease its volume while keeping the temperature constant?
Answer
(A)
Pressure increases.
29
What is the role of the fractionating column in fractional distillation?
Answer
(C)
To provide more surface area for the vapor to condense and revaporize.
30
Which statement(s) accurately describe(s) the particles in a solid?
Answer
A
C
31
What is the process where a liquid changes into a solid called?
Answer
(D)
Freezing
32
Which of the following statements are true regarding diffusion?
Answer
A
B
D
33
What happens to the volume of a gas if you increase its pressure while keeping the temperature constant?
Answer
(B)
The volume decreases.
34
What is the term for a liquid that is dissolved in another liquid or solid?
Answer
(A)
Solute
35
Which of the following describes the process of sublimation?
Answer
(C)
Solid changing directly to a gas.
36
What is measured in a graduated cylinder?
Answer
(B)
Volume
37
What is the name for the liquid that passes through the filter paper during filtration?
Answer
(B)
Filtrate
38
During which of the following processes is energy released?
Answer
C
D
39
What is the most precise method to measure 25 cm³ of a liquid?
Answer
(B)
A measuring cylinder
40
Which of the following is most important for diffusion to occur?
Answer
(C)
A concentration gradient
41
In paper chromatography, the stationary phase is made of:
Answer
(B)
The paper
42
Which of these is an example of a chemical property?
Answer
(C)
Reacting with acid
43
What property of a substance is determined by its 'R_f' value in chromatography?
Answer
(B)
Its solubility in the mobile phase
44
Which of these is a characteristic of a pure substance?
Answer
(B)
A distinct, sharp melting point.
45
What happens to the pressure of a gas if you increase its temperature while keeping its volume constant?
Answer
(A)
Pressure increases.
46
Which of the following increases the rate of diffusion?
Answer
B
D
47
Which of the following is NOT a property of solids?
Answer
(D)
Particles can move freely
48
Which statement best describes how a thermometer works?
Answer
(A)
The liquid expands when it is heated.
49
Which are the main steps involved in carrying out paper chromatography?
Answer
A
B
D
50
What do we call the movement of particles in a fluid (liquid or gas) from a region of high concentration to a region of low concentration?
Answer
(C)
Diffusion