Gen chem Spontaneous

[Ferdowsi]

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is this True:
all spontaneous reactions result in a nincrease in entropy of the universe?
well, if we have negative enthlapy and negative enropy and say temp is small number, then we'll have spontaneous reaction..I"m confused

 

[nixon13]

yes all spontaneous reactions do increase entropt of the universe.

D=delta

DG=DH-TDS
this equations is used to determine spontaniety.

DH= - and DS= + then reaction is spontaneous at all temps.
DH=+ and DS= - then reaction is not spontaneous.
DH= + and DS= + then reaction is spontaneous only at high temps.
DH= - and DS= + then reaction is spontaneous at low temps.

you can apply the equation above if they give you a problem dealing with any of those variables. Im pretty sure im right, but someone correct me if I said something wrong (its been a while).

 

[utdent20]

isn't it supposed to be DH- and DS- is spontaneous at low temp .. It hink thatis just a typo

 

[joonkimdds]

I know exactly why u r getting confused becuz u r trying to combine the 2nd law of spontaneous and Gibb's energy formula.
2nd law is talking about the entropy of the universe whereas Gibb's is talking about the entropy of system if I remember it correctly, if not...idk...i m so sleepy.