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 2COF2(g)⇌CO2(g)+CF4(g), Kc=9.00 If only COF2 is present initially at a concentration of 2.00 M, what concentration of COF2 remains at equilibrium?

Answer 1

`\boxed{\text{0.50 mol/L}}`

Step-by-step explanation:

The balanced equation is

2COF₂ ⇌ CO₂+CF₄; Kc = 9.00

1. Set up an ICE table

`\begin{array}{ccccc}\rm 2COF_(2) & \, \rightleftharpoons \, & \rm CO_(2) & +&\rm CF_(4)\\2.00& & 0& & 0\\-x& & +x & & +x\\2.00 - x& & x & &x \\\end{array}`

2. Solve for x

`K_(c) = ([\rm CO][ \rm CF_(4)])/([\rm COF_(2)]^(2)) = 9.00\\\\\begin{array}{rcl}(x^(2))/((2.00 - x)^(2)) & = & 9.00\\(x)/(2.00 - x) & = & 3.00\\x & = &3.00(2.00 - x)\\x & = & 6.00 - 3.00x\\4.00x & = & 6.00\\x & = & \mathbf{1.50}\\\end{array}`

3. Calculate the equilibrium concentration of COF₂

c = (2.00 - x) mol·L⁻¹ = (2.00 - 1.50) mol·L⁻¹ = 0.50 mol

`\text{The equilibrium concentration of COF$_(2)$ at equilibrium is $\boxed{\textbf{0.50 mol/L}}$}`

Check:

`\begin{array}{rcl}(1.50^(2))/(0.50^(2)) & = & 9.00\\\\(2.25)/(0.25)& = & 9.00\\\\9.00 & = & 9.00\\\end{array}`

OK.