Question

Given this equation: 2 H2 + O2 → 2 H2O, how many moles of O2 are needed to yield 3.8 moles of water?

Answer 1

Step 1 . write out a balanced reaction.

2H2 + O2 → 2H2O

Step 2 : Determine the mole proportion from the balanced equation.

From the balanced equation, we can see that :

- 1 mole of O2 gives : 2 mole H2O

- x mole O2 will give : 3.8 moles H2O.....(cross multiply)

∴ number of moles of oxygen required to give 3.8 moles of H2O

= 1/2 * 3.8 = x moles of O2

x = 1.9 moles

• This means that ,1.9moles of Oxygen ,will be needed to yield 3.8 moles of water.