Question

If the δh°soln of hno3 is –33.3 kj/mol, then how much heat is evolved by dissolving 0.150 mol hno3 in 100.0 ml of water?

Answer 1

Answer: - 5.00 kJ

Explanation:

1) The heat evolved during the reation is proportional to the number of moles dissolved.

2) Proportionality = ratio is constant

3) δh°soln of HNO3 is –33.3 kJ/mol => ratio 1

                  -33.3 kJ
ratio 1 = ---------------------
                 1 mol HNO3

4) ratio 2

        x
--------------
0.150 mol     

5) proportion

ratio 1 = ratio 2

        x                -33.3 kJ
--------------- =    -------------- => x = 0.150 mol * (-33.3kJ) / 1 mol = - 4.995 kJ ≈
0.150 mol              1 mol

≈ - 5.00 kJ