Question

1.what is the mass of a mole of water containing 50% of heavy water(D20)?
2.what is the mass of a molecule of carbon-14 dioxide?

Answer 1

1. mass of water will be 19 g mol 
2.the mass of a molecule of carbon-14 dioxide is 46g..

Answer 2

mass of water + 50% heavy water = 19 g
mass of carbon 14 dioxide = 7.636 × $10^{-23}$