Phosgene (carbonyl chloride), COCl2, is an extremely toxic gas that is used in m
ID: 894927 • Letter: P
Question
Phosgene (carbonyl chloride), COCl2, is an extremely toxic gas that is used in manufacturing certain dyes and plastics. Phosgene can be produced by reacting carbon monoxide and chlorine gas at high temperatures:
CO(g)+Cl2(g)COCl2(g)
Carbon monoxide and chlorine gas are allowed to react in a sealed vessel at 459 C . At equilibrium, the concentrations were measured and the following results obtained:
What is the equilibrium constant, Kp, of this reaction?
- - -
Part B
The following reaction was performed in a sealed vessel at 736 C :
H2(g)+I2(g)2HI(g)
Initially, only H2 and I2 were present at concentrations of [H2]=3.50M and [I2]=2.05M. The equilibrium concentration of I2 is 0.0200 M . What is the equilibrium constant, Kc, for the reaction at this temperature?
Express your answer numerically.
Gas Partial Pressure(atm) CO 0.720 Cl2 1.12 COCl2 0.180
Explanation / Answer
PART: A
CO(g) + Cl2(g) COCl2(g)
Given equilibrium partial pressure of CO is pCO = 0.720 atm
equilibrium partial pressure of Cl2 is pCl2 = 1.12 atm
equilibrium partial pressure of COCl2 is pCOCl2 = 0.180 atm
For the above reaction the equilibrium constant , Kp = pCOCl2 / ( pCO x pCl2 )
= 0.180 / ( 0.720 x 1.12 )
= 0.223
PART : B
H2(g) + I2(g) 2HI(g)
initial conc 3.50 2.05 0
change -a -a +2a
Equb conc 3.50-a 2.05 -a 2a
Given equilibrium concentration of I2 is [I2] = 0.0200 M
2.05 - a = 0.0200
a = 2.03 M
So equilibrium concentration of H2 is [H2] = 3.50 - a = 3.50 - 2.03 = 1.47 M
equilibrium concentration of I2 is [I2] = 0.0200 M
equilibrium concentration of HI is [HI] = 2a = 2x 2.03 = 4.06 M
The equilibrium constant , Kc = [HI]2 / ( [H2] [I2] )
= 4.06 2 / ( 1.47 x 0.0200 )
= 560.7