posted by Tim .
Consider the system I2 (g) <----> 2I (g) with H=+151 KJ. Suppose the system is at equilibrum at 1000 degree celsius. In which way will the reaction occur under each of the following conditions?
1. 1 atoms are added?
2. The temperture is increased?
3. The temperature is decreased?
4. The system is compressed?
It won't do any good for me to give you the answers. First, let's write the equation.
I2(g) + heat ==> 2I(g)
Now, Le Chatelier's Principle says that the reaction will shift so as to undo what is done to it.
1. I atoms are added. That increases I on the right, the reaction will want to decrease I (since we added I the reaction will try to undo that). The only way it can do that is to shift away from I which means a shift to the left.
2. T is increased. So the reaction will shift to use up the heat. How can it do that? By shifting to the right (again, away from what we added).
That does 1, 2, (and actually 3, too), Leaves you with 4 to reason through.