How many moles of water can be obtained from the reaction of 4 moles of O2?

Answer: 8moles

Explanation:

The reaction below shows the formation of 2 moles of water from 2 moles of hydrogen and 1 mole of oxygen respectively.

2H2 (g) + O2 (g) - -> 2H2O (l)

So, if 1 mole of O2 produce 2 mole of H2O

4 moles of O2 will produce Z mole of H2O

To get the value of Z, cross multiply

1 x Z = 4 x 2

Z = 8

So, the equation will be 8H2 (g) + 4O2 (g) - -> 8H2O (l)

Thus, 4 moles of O2 will produce 8moles of H2O.