Question
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 COF2(g) yeilds CO2(g) + CF_4(g),kc=4.70 If only m COF_2 is present initially at a concentration of 2.00 M, what concentration of m COF_2 remains at equilibrium?
Explanation / Answer
2 COF2(g) ? CO2(g) + CF4(g), => Kc = [CO2] · [CF4] / [COF2]² with Kc = 6.10 One mole of either carbon dioxide as of carbon fluoride are formed per 2 moles of carbonyl fluoride decomposed. Let x be the amount of COF2 decomposed and set up ICE table:, that means the rate of change Set up ICE table ----COF2-------CO2----------Cl2 I-----2.0----------0--------------0 C---(-x)-------(+x/2)-------(+x/2) E-(2.0-x)------(x/2)----------(x/2) Plug in the equilibrium concentrations to equilibrium condition and solve for x: 6.10 = (x/2) · (x/2) / (2.0-x)² 24.4 = x²/(2.0-x)² v24.4 = x/(2.0-x) x = 2.0 · v24.4 / ( 1 + v24.4) = 1.66 M Hence the equilibrium concentration of carbonyl fluoride is: [COF2] = 2.0M - 1.66M = 0.34M