10.Calculate the volume of oxygen that reacts with 500cm3 of hydrogen sulfide with the volume of both gases measured at rtp: 2H2S + 3O2 > 2SO2 + 2H20

0.79dm³

Explanation:

The reaction expression is given as:

            2H₂S   +   3O₂  →   2SO₂   +   2H₂O

Volume of hydrogen sulfide  = 500cm³ = 0.5dm³  

Unknown:

volume of oxygen that reacted  = ?

Solution:

 At rtp;        

                         22.4dm³ of gas has a mole of 1

            0.5dm³ will       = 0.022mole  of hydrogen sulfide;

                        2 mole of H₂S combines with 3 mole of O₂

           0.022 mole of H₂S will combine with   = 0.033mole of O₂

So;

   Since;

           1 mole of a gas occupied a volume of 22.4dm³ at rtp;

        0.033mole of Oxygen gas will occupy 0.033 x 22.4  = 0.79dm³

the product of the pressure and volume is also constant