Chapter 8, Problem 8.95P

The heat of solution of ammonia in water at 1 atm is

   $\Delta {\hat{H}}_s\left(25°C,r=2mol{H}_{2}O/molN{H}_3\right)=-78.2kJ/mol$

Calculate the enthalpy change that accompanies the dissolution of 200 mol of $N{H}_3$

1. in 400 mol of water at 25°C and 1 atm.

If you actually bubbled 200 mol of ammonia at 25°C through 400 mol of water initially at 25°C and calculated the heat released in the process as $Q=\Delta H$

,why would Q not equal the value you calculated in Part (a)? (Give two reasons.)