homework help

christinaT87 · 02-02-2005

Can you please help me understand my homework?

This is about Le Chateliers principle...

I have this equilibrium reaction:

CO(g) + H2O <---> CO2(g) + H2 (g) + energy

In which direction will the reaction go if you:

1) increase pressure?

2) increase temperature?

thank youu

Tim_Lou · 02-02-2005

1) well, it depends on the state of H2O, is it in gasous state? or liquid?
if it is vapor, increseing pressure will not affect the equilibrium, since both side have the same amout of molecules.
if it is in liquid state, incresing pressure will shift the equilibrium to the left, since increasing pressure favors a lesser volume.
(i doubt that H2O is in liquid state though, since CO2 will establish another equilibrium with water and forms H2CO3...

)

2) increasing temperature will increase the kinetic energy of the system, which can be counted as one of the "product", thus the equilbrium will shift to the left.

Fishteacher73 · 02-02-2005

Quote:

Originally Posted by Tim_Lou

2) increasing temperature will increase the kinetic energy of the system, which can be counted as one of the "product", thus the equilbrium will shift to the left.

Would not pressure also be a form of energy and thus push the equilibrium to the left as well?

Tim_Lou · 02-02-2005

pressure is not energy, it is force per area.
edit: the explanation i gave in this post before is totally irrelevant.

sciencegirl07 · 06-01-2008

assuming H2O is gaseous pressure would have no effect on the equilibrium, since pressure affects gaseous systems only where one side has less molecules than the other (equilibrium would shift to the side of the reaction where there are less molecules).
temperature increase=increase in average kinetic energy=equilibrium shift left, since the reaction is exothermic, and le chatelier's principle states that a chemical reaction will resist changes to its state of equilibrium (if i remember correctly).

modest · 06-02-2008

I agree with Tim_Lou.

Also, if you haven't got into calculating equilibrium constants yet - but are just looking at Le Chatelier's Principle conceptually, this should be a really good site:

Le Chatelier's Principle

-modest

//edit
One thing the site above does not note, but which will help you is that:

If energy is stated on the left side or reactants side of the equation then it should be taken as an endothermic reaction. If it is on the right side with the products it is an exothermic reaction.