From the equation CH4 + O2 = CO2 + H2O

From the equation CH4 + O2 = CO2 + H2O, How do I get 10 moles of H2O?

1. first, balance the equation.

CH4 + 2O2 --> CO2 + 2H2O

2. Multiply everything by 5

5CH4 + 10O2 --> 5CO2 + 10H2O

3. This means that it takes 5 moles of methane (CH4) and 10 moles of Oxygen (O2) to produce 10 moles of water (H2O).

first balance
CH4 + 2O2 = CO2 + 2H2O

multiply by 5

5CH4 + 10O2 + 5CO2 + 10H2O

so answer is combust 5 moles CH4 and 10 moles O2