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Homework Help: Question about Le Chatelier's Principle with regard to Temperature.

  1. Nov 23, 2008 #1
    1. The problem statement, all variables and given/known data This application makes no sense. The way I see it if, for example, the reaction temperature is increased and the reaction is endothermic, absorbing the heat to counteract the change makes no sense. If the temperature increases, the kinetic energy is increased, so releasing energy would seem to be the way to reduce the change in temp. What am I missing?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Nov 23, 2008 #2
    If a reaction is endothermic then it takes in heat. Which means that if we raise the temperature of the reaction we give it more heat to take in. Which in turn means that the reaction can form more products. The equilibrium changes.

    The same thing happens to an exothermic reaction if we lower the temperature. In this case it is basically beacause it is "easier" for the reaction to give out heat to a cold environment than it is to a hot one. e.g. Is it easier to put air into a tire which has a low pressure or a high pressure?

    Now you are saying "If the temperature increases then the kinetic energy increases." Which is correct. Then you go onto say "so realeasing energy would seem to be the way to reduce the change in temperature."

    If we realease energy then we are giving the surroundings more kinetic energy (an exothermic reaction). We don't want that. We want to minimize the effects of the change in temperature. And to do that we want to absorb that extra heat energy. The equilibrium will shift to the reactants side in this case.
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