Question

Ammonium nitrate absorbs 26 kj/mole of heat when it is dissolved in water. why does this compound readily dissolve in water? 1. ammonium ions and nitrate ions are more stable when surrounded by water than they are in the ionic solid. 2. as long as the temperature of the surroundings is sufficiently high to provide the required energy there is no reason why it shouldn't dissolve.

Answer 1

Missing answers:
3. All salts dissolve in water.
4. The resulting entropy increase in the system more than offsets the entropy decrease in the surroundings. Correct.
5. There is no observed change in entropy.
Gibbs free energy (G) determines if reaction will proceed spontaneously. If the value of G is a negative, the reaction is spontaneous. ΔG = ΔH - T·ΔS.
Because enthalpy of the system is greater that zero (endothermic), change in entropy (ΔS) must be positive if reaction is spontaneous.