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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: alex021095 on December 09, 2008, 08:59:12 AM

Title: Change in pressure or temperature from Equilibrium
Post by: alex021095 on December 09, 2008, 08:59:12 AM
Reaction: O2 + SO2  ->/<- SO3                              dH= -98.3kJ
What effect would the following changes have on the equilibrium concentration of
SO3? Give the explanation for each answer

a)Increasing the temperature of the reaction vessel

b)decreasing the total pressure

c)decreasing the volume of the reaction chamber

I'm not good at this problems....Could anyone help me~ ~?
Title: Re: Change in pressure or temperature from Equilibrium
Post by: Astrokel on December 09, 2008, 02:13:00 PM
well, show some work. Do you know about Le chatelier's principle? While there is this thread recently discussed about the principle but not exactly the same question as yours. check it out: http://www.chemicalforums.com/index.php?topic=30090.0
Title: Re: Change in pressure or temperature from Equilibrium
Post by: cliverlong on December 09, 2008, 03:36:46 PM
Another source of information for the equilibrium constant expressed in terms of partial pressures of gas, Kp, is:

http://www.chemguide.co.uk/physical/equilibria/kp.html

Clive
Title: Re: Change in pressure or temperature from Equilibrium
Post by: alex021095 on December 10, 2008, 08:38:54 PM
However i have a question in textbook that how adjust the volume of the reaction vessel in order to maximize product yield from : 2C(s) + O2(g) ≒2CO(g)

For my answer, I think it should be decreasing the volume,then the total pressure of the system will increases.The equilibrium position is shifted to the left to decrease the number of moles of gaseous molecules.Therefore,the product yield can be maximized.

But the correct answer is increasing the volume from text book....could you explain it to me~~?
Title: Re: Change in pressure or temperature from Equilibrium
Post by: macman104 on December 10, 2008, 08:41:52 PM
Wrong way.  To maximize the yield, you want to form as much product as possible.  Like you said, decreasing the volume will increase the pressure and shift the equilibrium to the left, and you want it to go to the right.