Aim
I am trying to investigate the effect of the mass of magnesium dioxide used on the speed of the reaction of 2H2O2(aq) 2H2O(l) + O2(g). I hypothesize that the speed of the reaction is proportional to the rate of decomposition.
Independent Variable
The mass of MnO2 used
Dependent Variable
The rate of decomposition through the amount of mass lost
Controlled Variables
Environment of the experiment Stay in the same place to carry out the experiment and finish the experiment as fast as possible in case of a sudden change in some areas of the environment
Volume of H2O2 used Measure the volume using a measuring cylinder
Uncontrollable Variable
The temperature of the H2O2 cannot be controlled because the process, which I am trying to speed up through adding catalysts, is an exothermic reaction, meaning that heat is given off in the process. Because it gives off heat, the temperature cannot be controlled and this would affect my results, as there would be more than one dependent variable. I was only allowed H2O2 from the same source, which means no fresh source of H2O2 at a controlled temperature. I could not wait for the H2O2 to decompose to a certain temperature because that would take too long. I could not use the catalysts to help the H2O2 to decompose to that temperature for the experiment to start because it would be difficult to gage when to take out the catalyst and catalysts are unable to be used up.
Equipment
Top pan balance
H2O2 – 300ml
MnO2 –5g
50ml Beakers - 10
Conical flasks - 5
Spatula
Cotton Wool
Measuring cylinder Diagram
Method
1. Gather the equipment and set it up like in the diagram above.
2. Using a top pan balance, a beaker and a spatula, measure 0.1g, 0.2g, 0.3g, 0.4g and 0.5g of MnO2 and place them in different beakers.
3. Measure 50ml of H2O2 using a measuring cylinder and fill 5 beakers with 50ml of H2O2 each.
4. Place a new conical flask and enough cotton wool to cover the hole of the