Question

24 g of carbon and 32 g of oxygen combine to form carbon monoxide. What is the mass of the carbon monoxide formed?

Answer 1

C = 12 grams / mol
O = 16 grams / mol
so 24 grams of C is 2 mols
and 32 grams of O is 2 mols of O and 1 mol of O2
2C + O2 --->2CO
so you get 12 + 16 = 28 grams

Answer 2

oops!! not 28 g.
2C + O2 ==> 2CO
mols C = g/atomic mass = 24/12 = 2
mols Oxygen = 32/32 = 1 mol O2
2 mols C will give 2 mols CO = 2*28 = 56 g CO OR
1 mol O2 will give 2 mols CO = 56 g CO Or to use the Law of conservatiion of matter this is
24 + 32 = 56 to start so 56 for the product total.