Calculate Ke for the following (equilibrium concentrations given below substances)?

Question

Calculate Ke for the following (equilibrium concentrations given below substances)

1. H2 (g) + Br2 (g) ↔ 2 HBr (g) + heat (HBr is underlined)

[0.513] [0.62] [0.346]

2. N2O4 (g) + heat ↔ 2 NO2 (g) (N2O4 is underlined)

[0.0325] [0.022]

3. NH4SH (g) ↔ NH3 (g) + H2S (g) + heat (NH3 is underlined)

[0.027] [0.0234] [0.209]

For all three of the equilibria in problem #1 predict (1) how Ke is affected by an decrease in temperature, (2) predict how the equilibrium will shift when pressure is increased, (3) predict how the equilibrium will shift when the concentration of the underlined substance is increased, and (4) predict how the equilibrium will shift when the temperature is increased.

Answer 1

1. H2 (g) + Br2 (g) ↔ 2 HBr (g) + heat (HBr is underlined)

[0.513] [0.62] [0.346]

K = [0.346]2 /[0.62] [0.513]

K = 0.376

(1) Ke is increased by an decrease in temperature, for equilibs that release heat as a product

(2) the equilibrium will NOT shift when pressure is increased, on equilibs that have the same # of moles of gases as products as thery have moles of starting materials

(3) <= <= <= it will shift to the other side of whatever is added

(4) the equilibrium will shift <= <= <= when the temperature is increased, in an exothermic reaction

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2. N2O4 (g) + heat ↔ 2 NO2 (g) (N2O4 is underlined)

[0.0325] [0.022]

K = [NO2}2 / [N2O4]

K = [0.022}2 / [0.0325]

K = 0.0149

(1) Ke is decreased by an decrease in temperature, for equilibriums that are endothermic

(2) the equilibrium will shift <= <= <=when pressure is increased to an equilibrium that has more moles of gases as products

(3) => => => it will shift to the other side of whatever is added

(4) the equilibrium will shift => => => when the temperature is increased, on equilibriums that have heat as a starting material

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3. NH4SH (g) ↔ NH3 (g) + H2S (g) + heat (NH3 is underlined)

[0.027] [0.0234] [0.209]

K = [ NH3] [H2S] / [NH4SH]

K = [ 0.0234] [0.209] / [0.027]

K = 0.181

(1) Ke is increased by an decrease in temperature, for equilibs that release heat as a product

2) the equilibrium will shift <= <= <=when pressure is increased to an equilibrium that has more moles of gases as products

(3) <= <= <= it will shift to the other side of whatever is added

(4) the equilibrium will shift <= <= <= when the temperature is increased, in an exothermic reaction