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Energy in reactions and rates of reactions 2023
By Sandra Kuhn
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Last updated about 1 year ago
16 questions
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Question 1
1.
D
B
A
C
Question 2
2.
The following energy profiles for four different reactions are shown below.
Which reaction is the most exothermic?
d
b
a
c
Question 3
3.
Consider the four energy profile graphs shown below:
Identify the two diagrams that could represent
the same reaction
catalysed and uncatalysed.
graph 1
graph 2
graph 3
graph 4
Graph showing reaction with catalyst present
Graph showing reaction with NO catalyst present
Question 4
4.
Which of the following reactions
releases
the
most
energy to the surroundings?
∆H = - 38 kJ/mol
∆H = + 1456 kJ/mol
∆H = - 456 kJ/mol
∆H = + 547 kJ/mol
Question 5
5.
Is the following statement True or False?
True
False
Question 6
6.
Consider the following potential energy profile with labels A - F.
Which label (A - F) matches each of the following?
A
B
C
D
E
F
The energy of the products?
The energy of the activated complex?
The activation energy (forward reaction)?
Heat of reaction/change in enthalpy?
The activation energy for the reverse reaction?
Question 7
7.
What TWO requirements are there for a collision to be effective/successful?
EXPT 1 - Consider the following experiment conducted to measure the rate of reaction between a metal and acid.
1
Question 8
8.
What change will DECREASE the rate of reaction?
Heating the flask
Using magnesium powder
Using a less concentrated acid
1
Consider the energy profile diagrams representing three different chemical reactions.
1
1
Question 12
12.
Which of the following units can be used to express the rate of a chemical reaction?
ml/g
mol/L
g/mol
mol/min
Question 13
13.
An 8 g piece of magnesium was placed into 6 mol.dm
-3
HCl. After 25 s, 3,50 g of unreacted magnesium remained.
The average rate at which magnesium was used up is:
0,14 g/s
0,18 g/s
0,32 g/s
4,50 g/s
Note that HCl is in excess.
Experiment 1 corresponds to graph B.
2
2
2
THE END OF THE ASSESSMENT
Check your answers and then click "submit"
Question 9
9.
Which of these Boltzmann distributions represents the effect of increasing the temperature of acid?
This effect cannot be shown on a Boltzman distribution curve
Question 10
10.
Which of these reactions is likely to proceed at the slowest rate?
Reaction A
Reaction B
Reaction C
They all have the same rate
Question 11
11.
Assume the that reaction C is a reaction between hydrogen and nitrogen to form ammonia.
The equation for Reaction C can be written as:
N
2
+ 3H
2
+ 30 kJ/mol ➝ 2NH
3
N
2
+ 3H
2
+ 50 kJ/mol ➝ 2NH
3
N
2
+ 3H
2
➝ 2NH
3
+ 50 kJ/mol
N
2
+ 3H
2
➝ 2NH
3
+ 30 kJ/mol
Question 14
14.
Experiment 2 is graph ....
A
C
D
Question 15
15.
Experiment 3 is graph .....
A
C
D
Question 16
16.
Experiment 4 is graph ....
A
C
D