## Test 2 Q 7 [ENDORSED]

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

Katherine Grillo 1B
Posts: 69
Joined: Fri Sep 28, 2018 12:28 am

### Test 2 Q 7

Why is the change in Gibbs free energy negative when ice melts? Isn't it gaining heat or in other words, isn't delta H positive?

annabel 2A
Posts: 67
Joined: Fri Sep 28, 2018 12:18 am

### Re: Test 2 Q 7  [ENDORSED]

Although deltaH is positive, deltaS is also positive (water is less orderly than ice), and deltaS*T is probably a greater value than deltaH which makes deltaG=deltaH-TdeltaS negative

taywebb
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

### Re: Test 2 Q 7

Because the outside environment is providing that heat directly, making this a naturally occurring reaction, no extra energy must be put in to make this reaction occur, so it is spontaneous.

Rehan Chinoy 1K
Posts: 67
Joined: Fri Sep 28, 2018 12:25 am

### Re: Test 2 Q 7

Just think about it conceptually -- the melting of ice is spontaneous in most temperatures, so deltaG should be negative.

Selina Bellin 2B
Posts: 62
Joined: Fri Sep 28, 2018 12:25 am

### Re: Test 2 Q 7

the situation is spontaneous bc there's nothing else that needs to be done to the ice in order to melt it

Jonathan Christie 1I
Posts: 32
Joined: Mon Apr 09, 2018 1:38 pm

### Re: Test 2 Q 7

I was wondering how to come to this conclusion, thank you