At 258C, Kp 5 2.9 3 1023 for the reactionNH4OCONH21s2m 2NH31 g21 CO21 g2In an experiment carried out at 258C, a certain amount of NH4OCONH2 is placed in an evacuated rigid container and allowed to come to equilibrium. Calculate the total pressure in the container at equilibrium.

0.27 atm

Explanation:

At 25ºC, Kp = 2.9 x 10⁻³ for the reaction NH₄OCONH₂(s) ⇌ 2 NH₃(g) + CO₂(g). In an experiment carried out at 25ºC, a certain amount of NH₄OCONH₂ is placed in an evacuated rigid container and allowed to come to equilibrium. Calculate the total pressure in the container at equilibrium.

Step 1: Make an ICE chart

Solid and liquids are ignored in ICE charts.

       NH₄OCONH₂(s) ⇌ 2 NH₃(g) + CO₂(g)

I                                            0             0

C                                        +2x           +x

E                                          2x             x

Step 2: Write the pressure equilibrium constant expression (Kp)

Kp = [NH₃]² × [CO₂]

Kp = (2x)² × x

2.9 × 10⁻³ = 4 x³

x = 0.090 atm

Step 3: Calculate the pressures at equilbrium

pNH₃ = 2x = 2(0.090 atm) = 0.18 atm

pCO₂ = x = 0.090 atm

The total pressure is:

P = 0.18 atm + 0.090 atm = 0.27 atm