Why are these answers on equilibrium wrong?

[ultimatelel]

I got the following answers wrong on my assignment (the ones highlighted)

For the decrease T (i assume they mean temperature), the reaction is exothermic as H <0, the amount of product would normally increase if a decrease in temperature occurred due to Le Chatelier, so would't the reaction be pushed forward and the amount of reactants decrease?

If I2 was added, there would be a net backward reaction so wouldn't K decrease (I know I wrote the wrong answer, but still don't understand why K wouldn't change)

If the volume was doubled, the system would move in the direction that had a greater number of particles, correct? However, I count 6 gas particles on each side of the equation, so wouldn't it have no effect?

Just realised that the catalyst one was marked wrong, it is in fact right. But why are the rest wrong? Thanks for any help

[thushan]

I got the following answers wrong on my assignment (the ones highlighted)

For the decrease T (i assume they mean temperature), the reaction is exothermic as H <0, the amount of product would normally increase if a decrease in temperature occurred due to Le Chatelier, so would't the reaction be pushed forward and the amount of reactants decrease?

If I2 was added, there would be a net backward reaction so wouldn't K decrease (I know I wrote the wrong answer, but still don't understand why K wouldn't change)

If the volume was doubled, the system would move in the direction that had a greater number of particles, correct? However, I count 6 gas particles on each side of the equation, so wouldn't it have no effect?

Just realised that the catalyst one was marked wrong, it is in fact right. But why are the rest wrong? Thanks for any help

Hey dude, watch my equilibrium position video on vTextbook - it gives you a comprehensive run down on Le Chatelier's principle and its relationship to K.

http://www.vtextbook.com/?p=watch&subject=5&unit=4&area=15&topic=39&video=1544069

As for the volume change question - it's the total number of gaseous and aqueous particles, not solid particles or liquid particles, since the latter two do not appear in the equilibrium expression.