Part A: Carbonyl fluoride, COF2, is an important intermediate used in the produc
ID: 487140 • 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=7.60
If only COF2 is present initially at a concentration of 2.00 M, what concentration of COF2 remains at equilibrium?
Part B: Consider the reaction
CO(g)+NH3(g)HCONH2(g), Kc=0.830
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
A) 2COF2 (g) <--> CO2 (g) + CF4 (g) , Kc = 7.6
at equilibrium [COF2] = 2-2X , [CO2] =[CF4] = X
K = [CO2] [CF4]/[COF2]^2
7.6 = X^2 / ( 2-2X)^2
7.6 = ( X/2-2X) ^2
X /2-2X = 2.76
X = 0.8465
[COF2] = 2-2(0.8465) = 0.307 M
B) at equilibrium [CO] 1=X , [NH3] = 2-X , [HCONH2] = X
Kc = [HCONH2] /[CO] [NH3]
0.83 = X/ ( 1-X) ( 2-X)
0.83 ( X^2 -3X+2) = X
0.83X^2 -3.49X + 1.66 = 0
X = 0.547
[HCONH2] = 0.547 M