A chemical reaction has a ΔHrxn of - 157 kj and a ΔSrxn of - 221 J/K. Is this reaction spontaneous at 525 K?

Question

A chemical reaction has a  ΔHrxn of - 157 kj and a  ΔSrxn of - 221 J/K. Is this reaction spontaneous at 525 K?

anonymous · Answer

Try using this equation: ΔG = ΔH - TΔS

aaronq · Answer

$\Delta G=\Delta H - T\Delta S$

the reaction is spontaneous when $\Delta G<0$

aaronq · Answer

ahh you beat me to it lol

anonymous · Answer

^ I left out the spontaneity part lol

aaronq · Answer

team work !

anonymous · Answer

(y)

anonymous · Answer

thanks guys

aaronq · Answer

np dude !

anonymous · Answer

the next question says though, at what temperature is the reaction at equilibrium

anonymous · Answer

anyone know?

anonymous · Answer

I think, but not entirely sure, that's when G=0. So just solve for T algebraically.

aaronq · Answer

yep, he's right. the reaction is at eq. when $\Delta G=0$

anonymous · Answer

yes but how would set that up to solve

anonymous · Answer

It's just substituting the values back into ΔG=ΔH−TΔS. We know that ΔG=0, and that ΔH and ΔS are still the same as stated in the question. The only variable in the equation is T, and it's what you need to find out.