Year 12 worksheet question.

[ShadowReeves]

im not entirely sure if this is the right place it. but here a question that i, or anyone else i know can answer. so maybe your collective minds can help me out.

 

Nitrogen dioxide NO2 decomposes when heated according to the equilibrium

 

2NO2 <--> 2NO + O2 for which K = 9.0 @ 910 degrees Celsius

 

analysis of a mixture of NO2, NO and O2 at 410 degrees C shows the concentrations of these species to be 2mol, 1mol and 2mol respectively.

 

a)is this an equilibrium mixture?

 

b) if the mixture is not an equlibrium mixture, which reaction - forward or reverse- will be favoured as the system moves to equilibrium.

 

that is word for word, there is no more information.

 

thanks

ShadowReeves

[hermanntrude]

OK you need to re-read your notes on the reaction quotient, Q.

 

The reaction quotient can be found by basically doing the same math as you would to find the equilibrium constant, but with non-equilibrium concentrations (or at least, concentrations you don't know are at equilibrium.

 

If Q>K, the reaction has gone too far and the reverse reaction will be favoured. If Q<K, the forward reaction will be favoured. A method many students like to use is to put the K first, so that the arrow (greater-than or less-than sign, < or >) points in the direction of the reaction that's favoured. If Q=K, the reaction is at equilibrium already. bear in mind you can only compare Kc with Kc and Kp with Qp.