Name:
Rates of Reaction
Hydrogen Peroxide solution decomposes slowly, releasing oxygen:
2H2O2 (aq)  2H2O (l) + O2(g)
The reaction is catalysed by manganese (IV) oxide, MnO2. Figure 1.1 shows the volume of oxygen
released with time when one measure of manganese (IV) oxide powder is added to 50cm3 of hydrogen
peroxide solution.
Time (s)
Volume of oxygen (cm3)
0
20
40
60
80
100
120
140
160
180
0
10
20
26
32
35
38
39
40
40
Figure 1.1
a) Draw a graph of volume of oxygen released (vertical axis) against time. Use a scale that goes up
to 100cm3.
[10]
b) On the same axes, sketch the graphs you would expect if, in separate experiments, use the
Roman Numerals to identify each answer.
[5]
0
i.
The temperature is raised to 40 C,
ii.
100cm3 of hydrogen peroxide solution is used,
iii.
Manganese (iv) oxide granules are used in place of powder,
iv.
50cm3 of hydrogen peroxide diluted to half its original concentration is used.
v.
If the catalyst is removed.
y
Scale:
x – axis: 1cm= 10 s
y – axis: 1cm= 10 cm3
90
80
70
60
50
40
X
ii
X
X
X a.
X
Volume of oxygen (cm3)
100
X
30
20
v
iii
i
X
X
10
X
0 X
0
20
40
iv
60
80
100
120
140
160
x
180
Time (s)
TITLE: GRAPH SHOWING THE RELATIONSHIP BETWEEN TIME AND THE
VOLUME OF OXYGEN