General Chemistry 2 Math Question 3

Question

i. For the reaction below, Kc = 0.66 at a certain temperature. If a reaction flask contains 1.35 M NO2, 1.35 M NO, and 1.25 M O2, will the equilibrium concentration of NO2 be greater than, less than, or equal to 1.35 M? Provide work or an explanation to justify your answer. 2 NO2(g) D 2 NO(g) + O2(g)

Answer 1

2NO₂(g) ==> 2NO(g) + O₂(g)

Kc = 0.66

Q = [NO]²[O₂] / [NO2]² = [1.35]²[1.25] / [1.35]²

Q = 1.25 Since this value is >> Kc (0.66) the reaction lies to the right (products). To get to equilibrium, the reaction will have to shift back towards the reactants, making the equilibrium [NO₂] greater than 1.35 M