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]=0.5 M, what will be the equilibrium concentration of NO2 if Kc=4?
0.1 M
0.2 M
0.3 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]=0.5 M, what will be the equilibrium concentration of NO2 if Kc=4?
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] = 0.5 M.
Step 3: Set up an ICE table (Initial, Change, Equilibrium) for the concentrations of NO, O2, and NO2.
Step 4: Fill in the initial concentrations in the ICE table: NO = 0.5 M, O2 = 0.5 M, NO2 = 0 M.
Step 5: 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 -0.5x.
Step 6: Write the equilibrium concentrations in terms of 'x': [NO] = 0.5 - x, [O2] = 0.5 - 0.5x, [NO2] = 0 + x.
Step 7: Write the expression for Kc: Kc = [NO2]^2 / ([NO]^2 * [O2]).
Step 8: Substitute the equilibrium concentrations into the Kc expression: 4 = (x^2) / ((0.5 - x)^2 * (0.5 - 0.5x)).
Step 9: Solve the equation for 'x'. After simplification, you will find that x = 0.2.
Step 10: Find the equilibrium concentration of NO2: [NO2] = x = 0.2 M.
Equilibrium Constant (Kc) – Understanding how to use the equilibrium constant to find concentrations at equilibrium.
ICE Table – Using the Initial, Change, Equilibrium (ICE) table method to track concentration changes during the reaction.
Stoichiometry – Applying stoichiometric coefficients from the balanced equation to relate the concentrations of reactants and products.
