Question

What is the mass of H2O produced when 10.0 grams of H2 reacts completely with 80.0 grams of O2?

Answer 1

H₂:

M=2g/mol
m=10g

n = m/M = 10g/2g/mol = 5mol

O₂:

M = 32g/mol
m = 80g

n = m/M = 80g/32g/mol = 2,5mol

2H₂        +            O₂          ⇒          2H₂O
2mol            :       1mol        :          2mol
5mol            :       2,5mol     :          5mol
10g              :       80g           :         10g+80g=90g

B