Question

Reaction is
CO2(g) + C(s) <=> 2CO(g)
Kp = 5.7, 1200K

Calcualte the total pressure at equilibrium when 4.45g CO2 is introduced into a 10.0L container and heated to 1200K in the presence of 2.00g of graphite

Answer 1

What effect does the mass of graphite have on this?

Answer 2

first step find the pressure exerted
pv=nRT
use this relation and find the pressure at initial state

Answer 3

so u get the patial pressure of CO2 and graphite
so this is the pressure at initial state
at equilibrium,
co2+ c------2co
pco2-k pc-k 2k

Kc=2k^2/pco2^2 *pc^2

Answer 4

How can a solid have partial pressure?

Answer 5

very good question!................is the graphite in pure form?

Answer 6

Yes

Answer 7

yes it should be then concentration=moles/volume=density/molar mass
density and molar mass being constant
graphite has concentration=1
therefore Pc=1

Answer 8

I do not understand what effect does the mass of graphite have on this question. The question after this asks me to do this entire process again but for mass of graphite = 0.50g...

Answer 9

Would not the graphite burn as well?

Answer 10

yes but not contribute to kc which we are bothered abt here
and to equilibrium concentration

Answer 11

So you are saying that in both cases, the answer is the same?
(ie. when it is 0.50g graphite, or the mass given in this question)...

Answer 12

yeah it souind vague but yeah thats the thing i am sure about it
it is only when u have 2gms of c that the raection proceeds if it were less then half the reaction will take place
wat i mewan by this is for 1 mol of co2 1 mol of c is to be present to give 2 mol of CO
so thats basically the idea

Answer 13

n1 =moles of CO2 (find them)
n2 = moles of C (find them)

CO2(g) + C(s) <=> 2CO(g)
n1 n2 0
-x -x +2x
n1-x n2-x 2x

Kp=P^2 (CO)/Pco2
..........use PV=nRT
Kp=(2x)^2/n1-x *RT/V solve to x

then P(total)=n(total)*R*T/V......Ptot=....

Answer 14

Salini, you might want to review. Both answers being the same is incorrect.

Answer 15

Mos, the Carbon solid is a constant. So it does not take place in an equilibrium ICE table.

Answer 16

yes you are right
i should put n(total) as n (gas total)=n(co2)+n(co)