## MarcLeclair 2 years ago URGENT! Consider the following decomposition reaction of ammonium carbonate ((NH4)2CO3): (NH4)2CO3 (s)  2 NH3 (g) + CO2 (g) + H2O (g) In one experiment at 25.0°C, a sample of pure (NH4)2CO3 is placed in an evacuated 2.00 L vessel. At equilibrium, the total pressure is found to be 0.8944 atm. (a) Determine the equilibrium partial pressure of each gaseous species. (b) Determine the mass of ammonium carbonate ((NH4)2CO3) that must have reacted in order to achieve equilibrium. (c) Determine the value of Kp assuming that the reaction temperature is 25.0°C. I can find a but I am stuck at b

1. Awstinf

use PV=nRT to find the moles and then convert back

2. MarcLeclair

but wait Im stuck with the ATM at equilibrium, the solid doesnt affect equilibrium at all, so how can I find it with the equilibrium of Pressure Don't I need concentration?

3. Awstinf

So you have pressure at EQ right?

4. Awstinf

4x=.8944

5. MarcLeclair

Yeah, the total, and I can use basic mole ratio to find individual pressure

6. Awstinf

solve for x then use the pressure for lets say CO2 put that into PV=nRT then solve for n then convert over

7. MarcLeclair

So I need to find n for one product than just use stoichiometry ?

8. Awstinf

yeah it should work.

9. Awstinf

let me work it out for you really fast

10. MarcLeclair

Alright ill try it and post if it works

11. Awstinf

(.2236)(2)/(298*.08206) = .0183*96g/mol = 1.76g

12. MarcLeclair

I cant beleive I didnt think of that, and for C , Q goes to infinity no? How to I possible use my Equilibrium constant equation?

13. MarcLeclair

How do I possibly*

14. Awstinf

for C? all you do is [NH3]^2[CO2][H2O]=Kp x=.2236 (2*.2236)^2(.2236)*(.2236)=.001

15. Awstinf

Not for PNH3 not [NH3] for each

16. MarcLeclair

Oh I thought you had to use ICE and Q to find the direction of the reaction :/ Apparently you don't thanks a lot!

17. Awstinf

Q is to judge where you are in respect to K if you have a larger Q you know you have far too many products so you need to get more reactants so the reaction goes to the left, if you have a small Q you know you have too many reactants and you need to go to products. you as in the reaction lol.

18. MarcLeclair

Ah I get it its just to judge the direction of the reaction BEFORE equilibrium but here we already reached it! Thanks a lot!

19. Awstinf

Yep you got it! good luck!