Consider a mixture of air and gasoline vapor in a cylinder with a piston. the original volume is 42 cm3. if the combustion of this mixture releases 927 j of energy, to what volume (in l) will the gases expand against a constant pressure of 656 torr if all the energy of combustion is converted into work to push back the piston?

Explanation:

Relation between work, pressure and volume is as follows.

                    W =

where,       W = work = -927 J (as energy is released so, work is done by the system)

                  P = pressure = 656 torr

                     = Pa          (as 1 torr = 133.3 Pa)

              Initial volume = 42

                                =           (as 1 m = 100 cm)

Hence, calculate the final volume as follows.

                W =

           -927 J =

                      =

                                      = 10.6 L            (as 1 = 1000 L)

                                      = 11 L (approx)

Thus, we can conclude that the gases expand 11 L against a constant pressure of 656 torr.