Find the volume of oxygen required to make 9 g of water.

1. Let’s compose the equation for obtaining water:

2H2 + O2 = 2H2O;

2.Calculate the chemical amount of the resulting water:

n (H2O) = m (H2O): M (H2O) = 9: 18 = 0.5 mol;

3. Determine the amount of required oxygen:

n (O2) = n (H2O): 2 = 0.5: 2 = 0.25 mol;

4. find the volume of oxygen:

V (O2) = n (O2) * Vm = 0.25 * 22.4 = 5.6 liters.

Answer: 5.6 liters.