Whta is the best way to memorise the effects of conc, temp and pressure on the position of equilibria and Kc?

  • 0 votes

I find that I always get confused between the three, especially when an exothermic or endothermic reaction is involved.

Posted Mon 19th November, 2012 @ 14:38 by Ashoo

3 Answers

  • 1 vote

Kc is only affected by tempreture. Kc is dependant on if the foward reaction is exothermic(-) or endothermic(+).

If the foward reaction is exothermic an increase in tempreture will decrease kc, a decrease in tempreture will increase the Kc. 

If foward reaction is endothermic, an increase in tempreture will increase kc, a decrease in tempreture in decrease Kc.

A change in concentration or tempreture only effects the position of the equilibrium, not KC. 

Answered Mon 19th November, 2012 @ 15:19 by Afsana
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Afsana

Thanks for the help, but I dont understand. In the first line you wrote: Kc is only affected by tempreture

and then on the last line you wrote:  A change in concentration or tempreture only effects the position of the equilibrium, not KC.

Is KC afftcted by temperature or not?

Answered Fri 23rd November, 2012 @ 00:05 by Ashoo
  • 0 votes

Yeah KC is only affected by tempreture. KC is the equilibrium constant. 

The position of the equilibrium is affected by changes in pressure and concentration. So if you have a high pressure and the number of moles on the right hand side is smaller than the left, the equilibrium will shift towards the right, so you get more product. Kc will be unaffected. 

Answered Sat 24th November, 2012 @ 12:39 by Afsana