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Essential Chemistry for IGCSE - Rate Of Reaction (Section 4)

1
Which of the following methods are used to investigate the rate of a reaction?
Answer
A
B
C
D
2
What is the main function of a catalyst in a chemical reaction?
Answer
(B)
To lower the activation energy
3
If you want to increase the rate of reaction using magnesium and hydrochloric acid, what can you do?
Answer
(C)
Increase the concentration of the acid
4
What happens to the average kinetic energy of the reactants when the temperature increases?
Answer
(B)
It increases.
5
What is the definition of a catalyst?
Answer
(B)
A substance that speeds up a chemical reaction without being consumed in the process.
6
If a graph of a reaction shows a plateau, what does it signify?
Answer
(A)
The reaction has stopped.
7
What is meant by the term 'activation energy'?
Answer
(B)
The minimum energy needed for a reaction to start.
8
What is the relationship between activation energy and the rate of reaction?
Answer
(B)
Higher activation energy means a slower reaction.
9
What happens to the particles in a reaction when temperature is increased?
Answer
(C)
They move faster and collide more frequently.
10
In the context of collision theory, what condition must be met for a collision between reactant molecules to be successful (result in a reaction)?
Answer
(B)
The molecules must collide with sufficient energy.
11
How does temperature affect the reaction rate, based on the collision theory?
Answer
(B)
Higher temperature increases the number of collisions and also increases the number of successful collisions.
12
Which of the following factors *directly* affects the rate of a chemical reaction?
Answer
(B)
The presence of a catalyst
13
According to collision theory, what is needed for a successful reaction to occur?
Answer
(C)
Molecules must collide with sufficient energy and correct orientation.
14
What is the role of surface area in reaction rates?
Answer
(C)
Increasing surface area increases the reaction rate.
15
How does increasing the concentration of reactants affect the number of collisions between reacting particles?
Answer
(C)
It increases the number of collisions.
16
What is meant by the term 'rate of reaction'?
Answer
(D)
All of the above.
17
What are the units usually used to express the rate of a reaction?
Answer
(D)
Moles per liter per second.
18
Which of the following are typical methods for monitoring the rate of a chemical reaction?
Answer
A
B
C
D
19
Which of the following is a key characteristic of an explosion?
Answer
(B)
A reaction that releases energy very quickly.
20
How does the rate of reaction change in the presence of a catalyst?
Answer
(C)
The reaction rate increases.
21
Which of the following is a common method to follow the progress of a reaction that produces a gas?
Answer
(B)
Measuring the loss of mass.
22
If you want to speed up a reaction, which of the following is the most effective strategy?
Answer
(B)
Increasing the temperature.
23
In a reaction involving a solid, how does decreasing the particle size of the solid reactant affect the reaction rate?
Answer
(C)
It increases the reaction rate.
24
What is the effect of adding a catalyst on the activation energy of a reaction?
Answer
(C)
It decreases the activation energy.
25
Which of the following is NOT a way to speed up a chemical reaction?
Answer
(B)
Decreasing the temperature.
26
What is the role of the 'activation energy' in a chemical reaction?
Answer
(B)
To provide a barrier that must be overcome for the reaction to proceed.
27
What is the effect of a catalyst on the activation energy?
Answer
(B)
It decreases it.
28
Which of the following can be followed to find out the rate of reaction?
Answer
A
B
29
What are some other ways to increase the rate of the reaction?
Answer
A
C
D
30
What happens to the rate of a reaction if you increase the surface area of the reactants?
Answer
(C)
It increases.
31
Why does increasing the temperature increase the rate of reaction?
Answer
(C)
It increases the kinetic energy of the reactant particles.
32
What is the initial step in following the progress of a chemical reaction?
Answer
(B)
Measuring how quickly the reactants are used up.
33
How does the addition of a catalyst affect the rate of a chemical reaction?
Answer
(B)
The rate increases.
34
What does the term 'activation energy' refer to in the context of chemical reactions?
Answer
(B)
The energy required to start a reaction.
35
When considering reaction rates, what is the significance of molecular orientation during collisions?
Answer
(C)
Correct orientation increases the chance of a successful reaction.
36
Which of the following statements are true regarding a reaction graph?
Answer
A
B
D
37
If a reaction is represented on a graph of the volume of gas produced versus time, what does the slope of the graph represent?
Answer
(B)
The rate of the reaction.
38
Why is a larger surface area of a solid reactant beneficial?
Answer
(A)
It increases the number of collisions between reactants.
39
What is the primary impact of a catalyst on a chemical reaction?
Answer
(C)
It increases the reaction rate.
40
Which of the following will change the rate of a chemical reaction?
Answer
A
B
D
41
Which of the following will change the rate of a chemical reaction?
Answer
A
C
42
Which of the following statements are true about a catalyst?
Answer
A
C
43
In the context of chemical reactions, which statement best describes 'collision theory'?
Answer
(C)
Reactions occur when reacting particles collide with sufficient energy.
44
In the context of investigating reaction rates, what does the term 'collision theory' refer to?
Answer
(B)
The theory that reactions occur when reactant particles collide with sufficient energy.
45
What is the primary function of a catalyst in a chemical reaction?
Answer
(B)
To increase the reaction rate.
46
What does a plateau on a graph showing the amount of product formed over time indicate?
Answer
(B)
The reaction has stopped.
47
Which of the following would decrease the rate of reaction?
Answer
(D)
Decreasing the temperature