Part A: Carbonyl fluoride, COF2, is an important intermediate used in the produc
ID: 637921 • Letter: P
Question
Part A: Carbonyl fluoride, COF2, is an important intermediate used in the production of fluorine-containing compounds. For instance, it is used to make the refrigerant carbon tetrafluoride, CF4 via the reaction 2COF2(g)?CO2(g)+CF4(g), Kc=5.10 If only COF2 is present initially at a concentration of 2.00 M, what concentration of COF2 remains at equilibrium? Express your answer with the appropriate units. Part B: Consider the reaction CO(g)+NH3(g)?HCONH2(g), Kc=0.770 If a reaction vessel initially contains only CO and NH3 at concentrations of 1.00 M and 2.00 M, respectively, what will the concentration of HCONH2 be at equilibrium?
Explanation / Answer
Part a
The balanced reaction with ICE TABLE
2COF2(g)?CO2(g)+CF4(g)
I 2
C - 2x +x +x
E (2-2x) x x
Equilibrium constant expression of the reaction
Kc = [CF4] [CO2] /[COF2]2
5.10 = (x2) / (2-2x)2
2.258 = x/(2-2x)
2.258(2-2x) = x
4.516 - 4.516x = x
4.516 = 5.516x
x = 0.8187
At equilibrium
Concentration of COF2 = 2 - 2x = 2-2*0.8187 = 0.3626 M
Part b
CO(g)+NH3(g)?HCONH2(g)
I 1 2
C -x -x +x
E (1-x) (2-x) x
Equilibrium constant expression of the reaction
Kc = [HCONH2] /[CO] [NH3]
0.77 = x / (1-x)(2-x)
(0.77-0.77x)(2-x) - x = 0
1.54 - 0.77x - 1.54x + 0.77x2 - x = 0
0.77x2 - 3.31x + 1.54 = 0
x = 0.5308
concentration of HCONH2 at equilibrium = x = 0.5308 M