# Kp equilibrium constant q

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#1
Hi!
I was hoping someone could just check my working for this question! Any help if it's incorrect is much appreciated

Here's my working:
Pressure of NO2 = 2 - 1.1 = 0.9atm
Kp = 0.9^2 / 2 = 0.405atm

0
1 month ago
#2
(Original post by kswales1)
Hi!
I was hoping someone could just check my working for this question! Any help if it's incorrect is much appreciated

Here's my working:
Pressure of NO2 = 2 - 1.1 = 0.9atm
Kp = 0.9^2 / 2 = 0.405atm

Try drawing a rice table. What do you think the pressure of N2O4 at equilibrium will be?
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#3
(Original post by Hellllpppp)
Try drawing a rice table. What do you think the pressure of N2O4 at equilibrium will be?
I'm not sure because I've never used a RICE table before, but here's what i did:

Since we know the pressure of NO2 dropped by 1.1atm, that means it's partial pressure is 2 - 1.1 = 0.9. Using the RICE table, this means that 2x = 0.9, so x=0.45. The pressure of N2O4 at equib. is 2-x, so 2 - 0.45 = 1.55? Once again i've never used a rice table before so im not even sure if i've used it correctly.
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1 month ago
#4
(Original post by kswales1)
I'm not sure because I've never used a RICE table before, but here's what i did:

Since we know the pressure of NO2 dropped by 1.1atm, that means it's partial pressure is 2 - 1.1 = 0.9. Using the RICE table, this means that 2x = 0.9, so x=0.45. The pressure of N2O4 at equib. is 2-x, so 2 - 0.45 = 1.55? Once again i've never used a rice table before so im not even sure if i've used it correctly.
You’ve got the right idea. C stands for change and its -1.1 for NO2. You’ve done the right thing dividing C by 2 and switching the sign for N2O4. What you’ll need to do is 2 + 0.55. Then you put this into the Kc equation.
Last edited by Hellllpppp; 1 month ago
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#5
(Original post by Hellllpppp)
You’ve got the right idea. C stands for change and its -1.1 for NO2. You’ve done the right thing dividing C by 2 and switching the sign for N2O4. What you’ll need to do is 2 + 0.55. Then you put this into the Kc equation.
I'm sorry for replying so late!! I'm confused though, where did the 0.55 come from?
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4 weeks ago
#6
(Original post by kswales1)
I'm sorry for replying so late!! I'm confused though, where did the 0.55 come from?
-1.1 divided by 2 then flip the sign from negative to positive because it’s on the other side of the reaction
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#7
(Original post by Hellllpppp)
-1.1 divided by 2 then flip the sign from negative to positive because it’s on the other side of the reaction
Ohh ok. So does that mean the partial pressure of the N2O4 is 2 - 0.55?
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4 weeks ago
#8
(Original post by kswales1)
Ohh ok. So does that mean the partial pressure of the N2O4 is 2 - 0.55?
It’s 2 + 0.55 because the partial pressure of NO2 falls so the pressure of N2O4 must rise
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