ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: kenhung123 on October 05, 2010, 11:33:07 pm
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I am a bit worried when explaining why changing volume, concentration etc won't change the equilibrium constant. Can you say because temperature is not changed which is the ONLY factor that changes the equilibrium constant for a reaction?
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Doesn't it have something to with the fact that for changes in volume/pressure/concentration, the ratio of products to reactants is the same at the new equilibrium, therefore K remains the same, however when the temperature changes, the ratio of products to reactants is different at the new equilibrium, therefore the value of K changes...
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From what I understand the temperature moves the reaction forward or backward depending on exo-endothermic reaction. i.e if it moves forward there will be more product, and hence a larger K value. Pressure or removing/adding will make the system re-adjust to the same concentration ratio as the original K value
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Yea but thats quite a long explanation for an exam question. Is just saying only temperature changes the K therefore if temp isnt changed, K doesnt change sufficient? I've seen Kilbaha do that so I am not sure if that is appropriate in the exams
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That would be a rather odd (and outside the course) question if they asked why it is only temperature that affects K. If you're talking about the exam that had a table where you had to say whether the factor would change K then you had to explain your answer then I think it would be sufficient to say that only temp changes K. You should, however, be comfortable with explaining how a temp change affects K in and endo/exo reaction with reference to LeChatelier's Principle.
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That would be quite odd. The explanation for temperature dependence can be found here in the section titled "Rate of reaction and Equilibrium Constant"
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Oh wow. That is such a comprehensive guide. Good work Mao