Spontaneous reactions

[705121606]

I know that having a negative delta g tells us that the reaction is spontaneous. When we are looking at delta s the total change in entropy being positive would also tell us the reaction would be spontaneous. Is this because a large delta s is being subtracted from delta h making delta g more negative?

[Aarja Pavade 1H]

If delta S is larger than delta H, it would make delta G negative (spontaneous). However, we would need to know the exact values for this. Another situation in which the reaction is spontaneous is if delta H is negative and delta S is positive. Subtracting a positive from a negative gives us a negative value for delta G, showing that the reaction is spontaneous. This situation doesn't require exact walls and is more general.

[Renee Grange 1I]

We can only tell if a reaction is spontaneous based on delta S alone is delta S total > 0. This is because spontaneous reactions follow the second law of thermodynamics, which is that entropy is always increasing. If delta S total is > 0, entropy is increasing and the reaction is spontaneous.

[BritneyP- 2c]

Having a larger delta S would make delta G smaller meaning it is spontaneous. If the delta S x T is still smaller than H, then that means the delta G is positive and not spontaneous, which is not favorable.