The Student Room Group

AQA A Level Chemistry Thermodynamics

When potassium nitrate (KNO3) dissolves in water the value of the enthalpy change
ΔH 34.9 kJ mol1
and the value of the entropy change ΔS 117 J K1 mol1
1.Deduce what happens to the value of ΔG when potassium nitrate dissolves in water at a temperature lower than your answer to part (c).

2.What does this new value of ΔG suggest about the dissolving of
potassium nitrate at this lower temperature

For this question in the beginning it gives entropy change as a positive value which I thought would mean that delta G is negative at higher temperatures ?And feasible at higher temperatures but instead the answer is that it becomes positive and the reaction is no longer feasible?
For the first one it says when the temperature becomes lower. So if the temperature becomes lower you are minusing a lower value from the enthalpy change, therefore the delta g value will become more positive

Quick Reply