A 20.9 g sample of nitrogen gas combines completely with 4.5 g of hydrogen gas to form ammonia. What is the mass of ammonia formed?

A 12.7 g sample of X combines with a 24.4 g sample of Y to form the compound XY2. What is the mass of the reactants?

1 answer

A. what is 20.9+4.5 g?

b. X mass given, as is y mass. Those are the masses of the reactants.