For the reaction 2NO(g) + O2(g) ⇌ 2NO2(g), if the initial concentrations are [NO
Practice Questions
Q1
For the reaction 2NO(g) + O2(g) ⇌ 2NO2(g), if the initial concentrations are [NO] = 0.5 M and [O2] = 0.2 M, what is the equilibrium concentration of NO2 if Kc = 10?
0.1 M
0.2 M
0.5 M
0.4 M
Questions & Step-by-Step Solutions
For the reaction 2NO(g) + O2(g) ⇌ 2NO2(g), if the initial concentrations are [NO] = 0.5 M and [O2] = 0.2 M, what is the equilibrium concentration of NO2 if Kc = 10?
Step 1: Write down the balanced chemical equation: 2NO(g) + O2(g) ⇌ 2NO2(g).
Step 2: Identify the initial concentrations: [NO] = 0.5 M and [O2] = 0.2 M.
Step 3: Write the expression for the equilibrium constant Kc: Kc = [NO2]^2 / ([NO]^2[O2]).
Step 4: Let x be the change in concentration of NO2 at equilibrium. Since 2 moles of NO produce 2 moles of NO2, the change for NO will be -x and for O2 will be -x/2.
Step 5: Write the equilibrium concentrations in terms of x: [NO] = 0.5 - x, [O2] = 0.2 - x/2, and [NO2] = x.
Step 6: Substitute these expressions into the Kc equation: Kc = x^2 / ((0.5 - x)^2 * (0.2 - x/2)).
Step 7: Set Kc equal to 10: 10 = x^2 / ((0.5 - x)^2 * (0.2 - x/2)).
Step 8: Solve for x. This may involve some algebraic manipulation and possibly using the quadratic formula.
Step 9: Once you find x, substitute it back to find [NO2] = x.
Step 10: The final answer for the equilibrium concentration of NO2 is found to be 0.4 M.
Equilibrium Constant (Kc) – Understanding how to apply the equilibrium constant expression to find concentrations at equilibrium.
ICE Table Method – Using an ICE (Initial, Change, Equilibrium) table to track changes in concentrations during the reaction.
