explain why a molar volume of a gas ar R.T.P.> gas at S.T.P.?

Question

explain why a molar volume of a gas ar R.T.P. is greater than thast of the gas at S.T.P.

Ｏ2→Ｏ3 {AT HIGH VOLTAGE ACROSS THE GAS}
WOULD THE MASS OF THE GAS BE CHANGED AFTER THE CONSERVATION ? EXPLAIN YOUR ANSWER.
PS: O2 IS oxygen , O3 is ozone

Answer 1

1. gases expand when they are heated, so it would be quite normal for the molar volume to increase between 0C and room temperature (taken as 25C).

2. 2O3 ----> 3O2 - the same number of oxygen atoms is present, and so there is no change in mass.