Question

6.1)the heat capacity for part 1 was 3064.78 J/K (part 1 was to determine the heat of neutralisation of strong acid and strong base) and the heat capacity for part 2 was 3.306 J/K ( part 2 was to determine the heats of dissolution of salts)

6.2) Q for BaCl2.2H2O = 15.83J

Q for CuSO4.5H2O = 8.55J

and Q for NH4NO3 = 27.26J

6. Questions 6.1. How does the heat capacity determined in this experiment compare with that determined in Part 1? 14) 6.2. Explain/rationalise the similarities and/or differences observed between the experimentally determined heats of dissolution for the different salts. 14]

Answer 1

6.1. In part 1 heat of neutralization was determined by using aqueous solutions of strong acid and bases. During dissolution of these acids and bases heat is generated but its effect was removed using their already prepared solutions. These solutions were mixed in the calorimeter.

For part 2 heat of dissolution of salts are determined by direct dissolving the salts in water in the calorimeter.

6.2. There are differences between heat of dissolutions of different salts. It depends on hydration energy of each salt. Every salt shows different extent of interaction with water (attractive interaction in the case). Or depends on hydration energy of a salt. So we get different heats of dissolution. As NH4NO3 shows higher energy than others means its attractive interaction with water is higher than others or its hydration energy is higher.