Represent the potential energy/enthalpy change in the following processes graphically.

1. Throwing a stone from the ground to roof. 

2.  12H2(g)+12Cl2(g)HCl(g);rH=-92.32kJmol-1

In which of the processes potential energy/enthalpy change is contributing factor to the spontaneity?


Representation of potential energy/enthalpy change in the following processes
(a) Throwing a stone from the ground to roof.
(b) 12H2(g)+12Cl2(g)HCl(g);rH=-93.32kJmol-1
Energy increases in (a) and it decreases in (b) process. Hence, in process (b), enthalpy change is the contributing factor to the spontaneity.