why would lowering the temp and decreasing the pressure not increase the rate of the reaction: carbon monoxide gas is combusted in the presence of oxygen gas into carbon dioxide. (DeltaH for this reaction is -285kJ.)

CO + O2 ==> CO2 + heat
decreasing P drives the reaction to the left (2 mols gas on left and only 1 right; therefore, increasing P drives reaction to right). Raising T drives the reaction to the left.

Better to use a balanced equation, it doesn't affect the argument in this case.

2CO + O2 ==> 2CO2 + heat

3 molescules gives 2 molecules but the argument is the same.

oops!. Dr Russ is right. I ALWAYS check to see if the equation is balanced (but not this time so I can't say always anymore.)