Or,
Now, for k=0.0174

Or,
.................................(2)
Again from van’t hoff equation

Or,
.............................................. (3)
From 1, 2, 3 we get

Substituting

We get,

Example 2:

A mixture of butane and 150% theoretical air enters a combustion chamber at 250c, 100kpa and products of combustion leaves at 1000K, 100kpa. Determine heat transfer from the combustion chamber and irreversibility of the process?

Solution

The stoichiometric equation is

Actual combustion equation with 150% theoretical air is,

Applying 1st law of thermodynamics,