Question

Why does ΔG for a reaction scale with reaction quantity but E does not? For example, ΔG0 rxn for the combustion of 1 mol of hydrogen is 1 × –237 kJ∕mol = –237 kJ, CHAPTER EXERCISES 73 while ΔG0 rxn for the combustion of 2 mol of hydrogen is 2 × –237 kJ∕mol = –474 kJ. In both

Answer 1

Answer:

This is as a result of their property type

ΔG is extensive and E is Intensive. The explanation is as given below

Explanation:

Basically both ΔG and the cell potential or the electromotive force (E.M.F) has some disparity especially in their spontaneity, for spontaneous reaction ΔG = -ve while E = +ve and vice versa. But the most important disparity is their state function i.e one is intensive and the other is extensive property.

ΔG is an example of an extensive property, they are properties whose value is dependent on the volume or the size of the system. other examples are mass, volume etc.

E on the other hand is an intensive property, they are properties whose value is not dependent on the size of the system. As such, this differences explains why ΔG for a reaction scale with a reaction quantity and E does not.