[GMAN20]

New to the forum so I hope I can get a response! I have two problems that I cannot seem to even get started on...

1. At 1000.15 K, the reaction equilibrium below has an equilibrium constant in terms of pressure (Kp) equal to 3.42.
2SO₂ (g) + O₂ (g)  2SO₃ (g)
If 2.65 mmol of SO₂ , 3.10 mmol of O₂ , and 1.44 mmol SO₃ are placed in a 185 mL vessel held at 1000.15 K, find the equilibrium amount of al species and find the equilibrium pressure.

2. The equilibrium below has a total pressure of 0.5451 atm at 363.15 K.
2 NaHCO₃ (s) Na₂CO₃ (s) + H₂O (g) + CO₂ (g)
a) Calculate Kp from this pressure
b) Calculate the total pressure if the NaHCO₃ (s) is placed into a container with 1 atm of CO₂ (g) (before reaction) at 363.15 K.


Anything will help
Thanks!

[Borek]

Start writing Kp for both systems.

First one is a direct application of ICE table, you just need to find initial pressures.

The second one is even easier - you can safely ignore both solids and concentrate on gases, which are (at least for a) present in equimolar quantities (because of the decomposition stoichiometry).

[GMAN20]

For number 1 when I express Kp is it acceptable to express it in molarities? I got:
Kp= 3.42 = (0.00778+2x)²/[(0.0143-2x)²(0.0168-x)]

The numerical values are simply the molarities of SO₂ (0.0143M), O₂(0.0168M), and SO₃(0.00778M).
Do I need to convert to partial pressures by using PV=nRT?

[Borek]

No need for molarities, and yes, PV=nRT is the way to go.

Or at least that's how I would approach the problem.