AP Chemistry Question of the Day --15

Here comes the answer to question 14 I posted yesterday. The correct answer is B. 
To Solve an equilibrium question, ICE table is always very helpful. ICE stands for Initial, Change and Equilibrium. 
Assume x atm of PCl5 converted to product at equilibrium, then

According to Dalton's Law of partial pressure, the total pressure is the sum of the individual pressures. At equilibrium, the total pressure is 1.40atm,

1.0-x+x+x=1.4

From the above equation, we can figure out that x=0.4. The equilibrium pressures of the three gases are 0.6atm. 0.4atm and 0.4atm. Kp can then be calculated:

So, the correct answer is B, Kp<1.

Following is Question 15 of the series. It is in continuation with question 12, 13 and 14. 

13. PCl5(g) decomposes into PCl3(g) and Cl2(g) according to the equation above. A pure sample of PCl5(g) is placed in a rigid, evacuated 1.00 L container. The initial pressure of the PCl5(g) is 1.00 atm. The temperature is held constant until the PCl5(g) reaches equilibrium with its decomposition products. The figures below show the initial and equilibrium conditions of the system. If the decomposition reaction were to go to completion, the total pressure in the container will be:

(A) 1.4 atm
(B) 2.0 atm
(C) 2.8 atm
(D) 3.0 atm

I will post the answer and explanation on Monday, Sept. 2nd. 

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