How many grams of water can be prepared from 8 grams of hydrogen at standard conditions?

Question

2 H2 (g) + O2(g) → 2 H2O

Answer 1

moles H2 = grams/molar mass = 8/2 = 4
Convert moles H2 to mols H2O this way using the coefficients in the equation.
4 moles H2 x (2 moles H2O/2 mols H2) = 4
Now convert moles H2O to grams H2O. g H2O = mols x molar mass = ?