Question

Each of the two flasks contains 2.0 g of gas at the same temperature and pressure. One flask contains oxygen and the other hydrogen. Which sample contains the greater number of molecules?

Answer 1

Flask having oxygen gas :
16g of oxygen gas has = 6.023 x 10²³ molecules.
2g of oxygen gas will have = 6.023 x 10²³/16 x 2 = 0.75 x 10²³
Flask having hydrogen :
1g of hydrogen has= 6.023 x 10²³ molecules.
2g of hydrogen gas will have = 6.023 x 10²³ x 2/1 = 12.05 x 10²³
So, hydrogen gas has greater number of molecules.