What is the mass of h2o produced when 14.0 grams of h2 reacts completely with 2.0 grams of o2?

Balanced chemical equation:

2 H2 + 1 O2 = 2 H2O

4 g H2  > 32 g O2 > 36 g H2O
   ↓                       ↓                             ↓
14.0 g > 2.0 g O2 > mass H2O ?

32 * mass H2O = 2.0 * 36

32 * mass H2O = 72

mass of H2O = 72 / 32

mass of H2O = 2.25 g

hope this helps!.

The correct name for n3-ion should be azide.