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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: dinosaur93 on November 10, 2012, 06:49:13 pm

Title: Le Chatelier's Principle
Post by: dinosaur93 on November 10, 2012, 06:49:13 pm
I know that when stating Le Chatelier's Principle, they can be very subjective in terms of word choice, How much should be write as a form of response in order to obtain the full mark?

for instance,

2NOBr(g) -----> 2NO(g) + Br2(g)

What would happen to the position of the equilibrium if the pressure was increased (decreased volume).

Due to increase of pressure, the equilibrium is no longer in equilibrium. According to Le Chatelier's Principle, the system will partially oppose the change (increase pressure) by favouring the side with the least amount of particles until the new equilibrium is established....


Is this enough for an answer?

What are some of the elements that are crucial to be seen in our response to get the marks in general? thank you! :)
Title: Re: Le Chatelier's Principle
Post by: datfatcat on November 10, 2012, 06:54:19 pm
Quote from: elvin.lam1 on November 10, 2012, 06:49:13 pm
I know that when stating Le Chatelier's Principle, they can be very subjective in terms of word choice, How much should be write as a form of response in order to obtain the full mark?

for instance,

2NOBr(g) -----> 2NO(g) + Br2(g)

What would happen to the position of the equilibrium if the pressure was increased (decreased volume).

Due to increase of pressure, the equilibrium is no longer in equilibrium. According to Le Chatelier's Principle, the system will partially oppose the change (increase pressure) by favouring the side with the least amount of particles until the new equilibrium is established....


Is this enough for an answer?

What are some of the elements that are crucial to be seen in our response to get the marks in general? thank you! :)

Say which side the reaction is heading. In this case, reverse reaction because there are fewer particles on the left hand side. :)
Title: Re: Le Chatelier's Principle
Post by: daniel034 on November 10, 2012, 06:56:40 pm
Quote from: elvin.lam1 on November 10, 2012, 06:49:13 pm
the equilibrium is no longer in equilibrium.

I would also change this sentence :D ;D
Title: Re: Le Chatelier's Principle
Post by: datfatcat on November 10, 2012, 06:57:28 pm
Quote from: daniel034 on November 10, 2012, 06:56:40 pm
Quote from: elvin.lam1 on November 10, 2012, 06:49:13 pm
the equilibrium is no longer in equilibrium.

I would also change this sentence :D ;D
HAHA i just spotted that :P
Title: Re: Le Chatelier's Principle
Post by: dinosaur93 on November 10, 2012, 06:58:40 pm
lol, *facepalm*

tnx guys~! :)
Title: Re: Le Chatelier's Principle
Post by: acinod on November 10, 2012, 06:59:06 pm
Quote from: elvin.lam1 on November 10, 2012, 06:49:13 pm
Due to increase of pressure, the equilibrium is no longer in equilibrium. According to Le Chatelier's Principle, the system will partially oppose the change (increase pressure) by favouring the side with the least amount of particles until the new equilibrium is established....

There are 3 key points you need to include:
-State the change in the system.
-State Le Chatelier's Principle and how it applies.
-State whether there is a net back/forward reaction.

So you just remember to include the last key point. My response would be something like the following:

Le Chatelier's Principle states that if there is a change to a system in equilibrium, the system will shift in order to partially oppose this change. Hence, as a result of an increase in pressure, the system will shift towards the side with less particles in attempt to partially decrease the pressure. This will result in a net forward reaction.

Hope that helps :)
Title: Re: Le Chatelier's Principle
Post by: michak on November 10, 2012, 07:00:02 pm
In these type of questions is it necessary to say "according to LCP" each time?