RR5:Does the amount of the catalyst manganese (IV) oxide change
during the decomposition of hydrogen peroxide?
IDEA
Oxygen is given off when hydrogen peroxide decomposes.
Each student group starts off with the same amount of hydrogen peroxide, but with different
amounts of manganese (IV) oxide (MnO2)
How much manganese dioxide MnO2 is used up, if any during the course of the chemical reaction ?
WORD EQUATION
manganese dioxide
catalyst
hydrogen peroxide
CHEMICAL EQUATION
manganese
dioxide catalyst
H2O2
APPARATUS
water
O2
+
+
oxygen
H2O
PROCEDURE
1.
Put a 1-2 spatulas of black manganese
dioxide into the evaporating basin.
2.
3.
Place the evaporating basin on a tripod.
4.
Now SLOWLY add 5-10 mls of
hydrogen peroxide onto the manganese
dioxide.
5.
A chemical reaction occurs.
Record its mass.
6.
The breakdown of hydrogen peroxide is
catalysed by the black manganese
dioxide.
7.
Heat the contents of the evaporating
basin gently until all the products have
been removed
DO NOT LET IT SPIT
8.
Let the evaporating basin cool down.
9.
Reweigh the evaporating basin and
contents.
10.
Mass before heating = ...........................g
11.
Mass after heating = ..............................g
CONCLUSION
In this experiment how did the mass of the catalyst before and after the experiment change ?
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FOR THE TECHNICIAN
HAZARDS
 Electronic balance
20 vol hydrogen peroxide
 Tripod
Corrosive – may cause burns
 Bunsen Burner
Dangerous if swallowed
 evaporating basin or tin lid
 manganese dioxide powder
Manganese dioxide
 20 vol hydrogen peroxide
Harmful if breathed in or swallowed.
small measuring cylinder