Question

If ΔG = ΔH - TΔS, when is the overall free energy change (ΔG) in a reaction most likely to be negative (meaning that the reaction is exergonic)?

A. when products have lower potential energy and higher entropy than reactants
B. when products have higher potential energy and lower entropy than reactants
C. when products have lower potential energy and lower entropy than reactants
D. when products have higher potential energy and higher entropy than reactants

Answer 1

http://www.shmoop.com/energy-flow-enzymes/free-energy.html
maybe this website can help u

Answer 2

Just look at the equation. It state everything, just remember that:
\[\Large \Delta _{r}H=\sum_{i}^{products} \Delta _{f}H-\sum_{j}^{reactants}\Delta_{f}H\]
Same applies for entropy.

Answer 3

Or look at it this way: divide the expression into two parts:
\[\Large \Delta G=\color{blue}{\Delta H}-\color{red}{T \times \Delta S}\]
Now we want to ensure that \(\color{blue}{\Delta H}\) is negative and \(\color{red}{T \times \Delta S}\) is positive (due to the minus sign). It should be simple algebra.