RATE OF REACTION
Lesmahagow High School
National 4/5 Chemistry
Topic 1 Multiple Choice Homework
-1-
1.
RATE OF REACTION
When calcium carbonate reacts with hydrochloric acid, carbon dioxide
gas is produced. A convenient way of following the reaction is to place a
flask containing the reactants on a chemical balance and follow the
mass of the apparatus with time. As carbon dioxide escapes from the
flask it loses mass.
The results of such an experiment are shown below.
235
MASS (g)
234.5
234
233.5
233
232.5
232
0
1
2
3
4
5
TIME (MINUTES)
(a) What was the final mass of the apparatus when the reaction stopped?
A. 232.6 g
B. 232.3 g
C.
232.5 g
D. 232.7 g
(b) When did the reaction stop?
A. 3.0 min
B. 3.5 min
C.
4.0 min
D. 4.5 min
-2-
RATE OF REACTION
(c) What was the total loss in mass?
A. 2.1 g
B. 2.2 g
C.
2.4 g
D. 2.5 g
(d) What mass of carbon dioxide has been produced at time = 1.25 minutes?
A. 1.4 g
B. 1.6 g
C.
1.8 g
D. 2.0 g
(e) What was the average rate of reaction from time = 0 to 2 minutes?
A. 0.9 g min-1
B. 1.0 g min-1
C.
1.05 g min-1
D. 1.2 g min-1
(f) What was the average rate of reaction from time = 2 to 4 minutes?
A. 0.2 g min-1
B. 0.25 g min-1
C.
0.3 g min-1
D. 0.1 g min-1
A diagram of the apparatus used to follow the above reaction is shown below
COTTON WOOL PLUG
CONICAL FLASK
CALCIUM
CARBONATE AND
HYDROCHLORIC ACID.
CHEMICAL
BALANCE
-3-
RATE OF REACTION
(g) The purpose of the cotton wool plug is
A. To seal the flask and prevent any gas or acid spray leaving the flask
B. To prevent acid spray leaving the flask, but allow carbon dioxide
through
C.
To prevent carbon dioxide leaving the flask, but allow acid spray
through
D. To allow both acid spray and carbon dioxide gas to leave the flask
(h)
A.
B.
C.
D.
A very bright pupil said that some of the carbon dioxide gas might
dissolve in the acid solution. She argued that the acid solution contains
a lot of water and she knew that carbon dioxide gas dissolves in fizzy
drinks which also contain a lot of water.
If some of the carbon dioxide did dissolve in the acid then
The masses recorded will be smaller than they should be
The masses recorded will be larger than they should be
The masses recorded will be unaffected by any carbon dioxide
dissolving
It is impossible to say what effect this will have on the masses
recorded.
-4-
2.
RATE OF REACTION
The graph below shows the volume of gas produced when calcium
carbonate reacts with dilute hydrochloric acid to produce carbon
dioxide gas. The volume of gas was measured against time.
70
VOLUME (cm3)
60
50
40
30
20
10
0
0
20
40
60
TIME (SECONDS)
(a) When did the reaction stop?
A. At 60 seconds?
B. At 80 seconds?
C.
At 100 seconds?
D. At 120 seconds?
(b) What was the final volume of gas produced?
A. 64 cm3
B. 54 cm3
C.
44 cm3
D. 34 cm3
-5-
80
100
RATE OF REACTION
(c) The volume of gas produced after 35 seconds was
A. 24 cm3
B. 34 cm3
C.
44 cm3
D. 54 cm3
(d) The time taken to produce 30 cm3 of gas was
A. 23 seconds
B. 13 seconds
C.
33 seconds
D. 8 seconds
(e) The average rate of evolution of gas in the first 10 seconds was
A. 0.024 cm3 s-1
B. 0.24 cm3 s-1
C.
2.4 cm3 s-1
D. 24 cm3 s-1
(f) The average rate of evolution of gas between 10 and 20 seconds was
A. 0.015 cm3 s-1
B. 0.15 cm3 s-1
C.
1.5 cm3 s-1
D. 15 cm3 s-1
(g) The average rate of evolution of gas between 20 and 30 seconds was
A. 11 cm3 s-1
B. 1.1 cm3 s-1
C.
0.11 cm3 s-1
D. 0.011 cm3 s-1
(h) The reaction was fastest at
A. time = 20 seconds
B. time = 80 seconds
C.
time = 50 seconds
D. time = 10 seconds
-6-
3.
A.
B.
C.
D.
4.
A.
B.
C.
D.
5.
A.
B.
C.
D.
6.
A.
B.
C.
D.
RATE OF REACTION
A particular reaction produced 120 cm3 of gas in 30 seconds. The
average rate of reaction in this time was
0.25 cm3 s-1
4 cm3 s-1
30 cm3 s-1
120 cm3 s-1
A particular reaction produced 200 cm3 of gas in 20 minutes. The
average rate of reaction in this time was
0.1 cm3 min-1
10 cm3 min-1
20 cm3 min-1
200 cm3 min-1
The rate of a chemical reaction was found to be 60 cm3 min-1, the rate
of reaction in cm3 s-1 would be
1
10
60
3600
A chemical reaction, which produced a gas, was followed by measuring
the loss in mass of the container with time. The container lost 2.4 g in 4
minutes. The average rate of reaction during this time was
0.4 g min-1
2.4 g min-1
6.0 g min-1
0.6 g min-1
7. Which of the following would increase the rate of a chemical reaction?
A. Keeping the mass constant but increasing the particle size
B. Decreasing the temperature
C.
Increasing the concentration
D. Decreasing the concentration
8.
A.
B.
C.
D.
Which of the following would decrease the rate of a chemical reaction?
Keeping the mass constant but increasing the particle size
Keeping the mass constant but decreasing the particle size
Increasing the temperature
Increasing the concentration
-7-
RATE OF REACTION
9.
A
B
C
D
10.
A
B
C
D
The reaction between copper (II) carbonate and sulfuric acid produces
carbon dioxide gas. Which of the following conditions will give the
fastest rate of reaction?
Concentration of
acid
/ mol l-1
1
1
2
2
Temperature of acid
/ C
Particle size of copper
(II) carbonate
20
30
20
30
Lump
Powder
Lump
Powder
The reaction between magnesium metal and sulfuric acid produces
hydrogen gas. Which of the following conditions will give the slowest
rate of reaction?
Concentration of
acid
/ mol l-1
1
1
2
2
Temperature of acid
/ C
Particle size of copper
(II) carbonate
20
40
20
40
Lump
Powder
Lump
Powder
-8-