Question

How many moles of water (H2O) would be produced if 10 moles of O2 gas reacted completely with excess H2 gas?

2 H2(g) + O2(g) → 2 H2O(g)

A. 5
B. 10 
C. 20
D. 30 

Answer 1

2 H2(g) + O2(g) → 2 H2O(g)

according to the reaction:
1 mole of O2-----------------2 moles of H2O
10 moles of O2--------------------- x
x = 20 mole of H2O

answer: C

Answer 2

C. 20

Step-by-step explanation:

Use the equation to know that 1 mol of O2 is equal to 2 mol H2O.

Now you will start with the data, this is 10 mol O2 and you obtain:

10 mol O2 x 2 mol H2O = 20 mol H2O

1 mol O2