How much and how much oxygen is required for the complete combustion of 1 liter of hydrogen sulfide?

At the beginning, let’s draw up the reaction equation for the combustion of hydrogen sulfide.

2H2S + 3O2 = 2H2O + 2SO2

The reaction for 2 moles of hydrogen sulfide requires 3 moles of oxygen.

And since 1 mole of any gas in normal conditions occupies equal volumes, the number of liters of oxygen is determined by dividing the number of liters of hydrogen sulfide by 2 and multiplying by 3. As a result, we get the correct answer, namely 1.5 liters (oxygen). But this is theory. In practice, a small excess is required for complete combustion, since chemical reactions do not really proceed 100%.