Question

Which is heavier one mole of oxygen gas or 44 g of carbon dioxide??

Answer 1

For carbon dioxide, there is one carbon atom (weight 12) and two oxygen atoms (mass 16 x 2) for a total of 44.

This means that carbon dioxide should be about 44/32 = 1.375 times as heavy as an equivalent volume of oxygen.

Answer 2

44 g of carbon is heavier than 1 mole of oxygen