If the enthalpy change of a reaction is ∆H how will you calculate entropy of surrounding?
Answers
Answer:
keep smiling....
Explanation:
Calculating the entropy change of the surroundings.
So far, you know how to work out the entropy change of the system for a given reaction if you are told the entropies of all the substances involved in the reaction.
There is a simple equation for the entropy change of the surroundings.
ΔH is the enthalpy change for the reaction. T is the temperature.
That seems easy, but there is a major trap to fall in here, and if you manage to get through your course without falling into it at least once, you will have done really well!
There is a mismatch between the units of enthalpy change and entropy change. When you quote figures for enthalpy change they will have energy units of kJ. But entropy change is quoted in energy units of J.
That means that if you are calculating entropy change, you must multiply the enthalpy change value by 1000.
So if, say, you have an enthalpy change of -92.2 kJ mol-1, the value you must put into the equation is -92200 J mol-1.
If the temperature was 298 K . . .
Notice that the negative sign in the equation converts the negative exothermic enthalpy change into a positive entropy change. An exothermic change heats the surroundings, and increases the entropy of the surroundings.
Working out the total entropy change
If, for example, the entropy change of the reaction (the system) was +112 J K-1 mol-1, then the total entropy change would be