Monitoring the production of a gas using gas collection

Question 1

Write the equation for the decomposition of hydrogen peroxide?

Answer 1

2H2O2 (aq) —-> (MnO2 catalyst) —-> 2H2O (l) + O2 (g)

Question 2

Write a method to find the production of gas during the decomposition of hydrogen peroxide

Answer 2

Hydrogen peroxide is added to the conical flask and the bung is replaced
The initial volume of gas in the measuring cylinder is recorded
Manganese dioxide, MnO2, catalyst is then quickly added to the conical flask and the
bung is replaced
A stop clock is started
The volume of gas produced in the measuring cylinder is recorded at regular intervals until the reaction is complete
The reaction is complete when no more gas is evolved

Question 3

What explanations are consistent with collecting a lower total volume of gas than we would expect from moles calculations?

Answer 3

Some gas dissolves in the water
Some gas is lost before the bung is replaced