Question

The decomposition of NH4Cl can be accomplished by heating it in an evacuated cylinder. The products are NH3 and HCl gas. If the total pressure after heating is 4.4 atm, determine Kp.

Please help me with the steps on how to do solve this.

Answer 1

........NH4Cl(s) ==> NH3(g) + HCl(g)
I......solid.........0.........0
C......solid.........p.........p
E......solid.........p.........p

Kp = pNH3*pHCl
The problems tell you that pNH3 + pHCl = 4.4 atm and since pNH3 = pHCl that makes 2p = 4.4 and p = 2.2 atm
Substitute into Kp expression and solve for Kp.

Answer 2

Thank you!!