Answer:
Step-by-step explanation:
Let the number of moles of oxygen = x
2H2 + O2 --> 2 H2O
x 13.3
Since the balance number for oxygen is 1 and the balance number for water is 2, you must set up a proportion. (Those balance numbers represent the number of moles).
1/x = 2 / 13.3 Cross Multiply
2*x = 13.3 Divide both sides by 2
2x/2 = 13.3/2
x = 6.65
You need 6.65 moles of oxygen.