00:03
So this question is asking why for exothermic reactions, there are normally spontaneous at lower temperatures.
00:11
And as you increase temperature, it tend to become non -spontaneous.
00:15
So we need to go back to what determines if a reaction is spontaneous or non -spontaneous.
00:20
And for that, we look at delta g.
00:23
So delta g is positive, reaction is non -spontaneous.
00:35
And if delta g is negative, the reaction is spontaneous.
00:37
And for an exothermic reaction delta h is negative because heat is given off to surroundings so now i need to relate these two variables to each other so delta g equals delta h minus t delta s and so now i need to think about all right if delta h is always negative then what would make delta g negative so temperature is always positive.
01:31
So only thing that can affect this is the scale of temperature and whether entropy is negative or positive...