A chemist prepared a sealed tube with 0.85 bar of PCl5 at 500 K. The pressure increased as the following reaction occurred. When equilibrium was achieved, the pressure in the tube had increased to 1.25 bar. Calculate Kp.PCl5(g) ⇌ PCl3(g) + Cl2(g)Group of answer choices0.360.190.100.0470.089

The reaction given is: PCl5(g) ⇌ PCl3(g) + Cl2(g)

The initial pressure of PCl5 is 0.85 bar. When the reaction reaches equilibrium, the total pressure in the tube is 1.25 bar. This means that the pressure has increased by 1.25 - 0.85 = 0.40 bar.

Since the reaction produces one mole of PCl3 and one mole of Cl2 for every mole of PCl5 that reacts, the increase in pressure is due to the production of these two gases. Therefore, at equilibrium, the pressures of PCl3 and Cl2 are each 0.40/2 = 0.20 bar, and the pressure of PCl5 is 0.85 - 0.40 = 0.45 bar.

The expression for Kp for the reaction is:

Kp = (PCl3 * Cl2) / PCl5

Substituting the equilibrium pressures into this expression gives:

Kp = (0.20 * 0.20) / 0.45 = 0.089

So, the correct answer is 0.089.

The reaction given is:

PCl5(g) ⇌ PCl3(g) + Cl2(g)

The initial pressure of PCl5 is 0.85 bar. At equilibrium, the total pressure is 1.25 bar. This means that the pressure of PCl5 has decreased and the pressures of PCl3 and Cl2 have increased.

Let's denote the decrease in pressure of PCl5 as x. Therefore, the increase in pressure of PCl3 and Cl2 is also x (since for every mole of PCl5 that reacts, one mole of PCl3 and one mole of Cl2 are produced).

So at equilibrium, we have:

PCl5 = 0.85 - x bar PCl3 = x bar Cl2 = x bar

The total pressure at equilibrium is 1.25 bar, so:

0.85 - x + x + x = 1.25 2x = 1.25 - 0.85 2x = 0.4 x = 0.4 / 2 x = 0.2 bar

So the equilibrium pressures are:

PCl5 = 0.85 - 0.2 = 0.65 bar PCl3 = 0.2 bar Cl2 = 0.2 bar

The expression for Kp is:

Kp = (PCl3 * Cl2) / PCl5

Substituting the equilibrium pressures into this expression gives:

Kp = (0.2 * 0.2) / 0.65 = 0.04

So the answer is 0.04.