equilibrium constant

~GrOoVy~ · 13 Aug 2005, 9:55 PM

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okay i know that it is temperature dependent, but I want to know when it increases and decreases in an exothermic or an endothermic reaction...that doesn't sound right but can someone answer this question plz...its killing me

thanks

velox · 13 Aug 2005, 10:05 PM

Exothermic reactions will have an increase in their equilibrium constant when the temperature is lowered. Correspondingly Endothermic reactions will have a decrease in their equilibrium constant when the temperature is lowered.

xrtzx · 14 Aug 2005, 12:46 PM

since u know the equilibrium constant is products/reactants

so for exo reactions, if we increase the equil will shift to the left, this reduces products producing more reactants so the equil constant decreases, but if we decrease the temp of an exo reaction the equilibrium will shift to the right, so more products so equilibrium constant increases etc etc

elitus · 18 Aug 2005, 12:21 AM

I'll just answer it with a tad more precision:

1. If forward reaction is exothermic:

a) A decrease in temp will shift the equilibrium to the right. Because: The change is a decrease in temp, in order to counteract the change, the reaction must produce heat. Thus the reaction moves forward.

b) An increase in temp will shift the equilibrium to the left. Because: The reverse reaction is endothermic. The change is a increase in temp, in order to counteract the change, the reaction must absorb the heat. Thus the reaction moves backwards.

2. If forward reaction is endothermic:

a) An increase in temp will shift the equilibrium to the right. Because: The change is a increase in temp, in order to counteract the change, the reaction must absorb the heat. Thus the reaction moves forward.

b) A decrease in temp will shift the equilibrium to the left. Because: The reverse reaction is exothermic. The change is an increase in temp, in order to counteract the change, the reaction must produce heat. Thus the reaction moves backwards.

It all follows Le Chatelier's Principle where an equilibrium alters to counteract the change and a new equilibrium is established.

~GrOoVy~ · 18 Aug 2005, 1:17 PM

thanks guys...i finally get this thingy

13 Aug 2005, 9:55 PM	#1 (permalink)
~GrOoVy~ cough hahahhaa cough HSC: 2005 Gender: Female Location: right behind you...AARRGGHHH Join Date: Sep 2003 Posts: 84 Last Activity: 7 Dec 2005, 12:54 PM	equilibrium constant You can hide this advertisement by registering. okay i know that it is temperature dependent, but I want to know when it increases and decreases in an exothermic or an endothermic reaction...that doesn't sound right but can someone answer this question plz...its killing me thanks

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13 Aug 2005, 10:05 PM	#2 (permalink)
velox Retired HSC: N/A Gender: Male Location: Where the citi never sleeps. Join Date: Mar 2004 Posts: 5,546 Last Activity: 13 Mar 2010, 10:35 PM	Exothermic reactions will have an increase in their equilibrium constant when the temperature is lowered. Correspondingly Endothermic reactions will have a decrease in their equilibrium constant when the temperature is lowered.

14 Aug 2005, 12:46 PM	#3 (permalink)
xrtzx i <3 /\/\0\|)s HSC: 2010 Gender: Undisclosed Location: on ur doorstep Join Date: Oct 2004 Posts: 1,354 Last Activity: 12 Apr 2006, 10:05 PM	since u know the equilibrium constant is products/reactants so for exo reactions, if we increase the equil will shift to the left, this reduces products producing more reactants so the equil constant decreases, but if we decrease the temp of an exo reaction the equilibrium will shift to the right, so more products so equilibrium constant increases etc etc

18 Aug 2005, 12:21 AM	#4 (permalink)
elitus New Member HSC: N/A Gender: Male Join Date: Oct 2004 Posts: 17 Last Activity: 24 Jan 2007, 7:02 PM	I'll just answer it with a tad more precision: 1. If forward reaction is exothermic: a) A decrease in temp will shift the equilibrium to the right. Because: The change is a decrease in temp, in order to counteract the change, the reaction must produce heat. Thus the reaction moves forward. b) An increase in temp will shift the equilibrium to the left. Because: The reverse reaction is endothermic. The change is a increase in temp, in order to counteract the change, the reaction must absorb the heat. Thus the reaction moves backwards. 2. If forward reaction is endothermic: a) An increase in temp will shift the equilibrium to the right. Because: The change is a increase in temp, in order to counteract the change, the reaction must absorb the heat. Thus the reaction moves forward. b) A decrease in temp will shift the equilibrium to the left. Because: The reverse reaction is exothermic. The change is an increase in temp, in order to counteract the change, the reaction must produce heat. Thus the reaction moves backwards. It all follows Le Chatelier's Principle where an equilibrium alters to counteract the change and a new equilibrium is established.

18 Aug 2005, 1:17 PM	#5 (permalink)
~GrOoVy~ cough hahahhaa cough HSC: 2005 Gender: Female Location: right behind you...AARRGGHHH Join Date: Sep 2003 Posts: 84 Last Activity: 7 Dec 2005, 12:54 PM	thanks guys...i finally get this thingy