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

Question

a) 4 NH3 (g) + 3 O2 (g) ↔ 2 N2 (g) + 6 H2O (g) + heat

[0.010] [0.10] [0.0794] [0.10]

b) N2 (g) + 3 H2 (g) + heat ↔ 2 NH3 (g)

[0.103] [0.240] [0.0114]

c) H2 (g) + Cl2 (g) ↔ 2 HCl (g) + heat

[0.21] [0.22] [0.784]

2. 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

a) 4 NH3 (g) + 3 O2 (g) ↔ 2 N2 (g) + 6 H2O (g) + heat

K = [N2]^2 [H2O]^6  / [NH3]^2 [O2]^3

K = [0.0794]^2 [0.1]^6  / [0.01]^2 [0.1]^3

K = 6.3e-9 / 1e-7

K = 0.063

(1) when heat is a product,... Ke increases with a  decrease in temperature,

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

(3) no body is underlined , but it will shift to the other side of whatever is added

(4)  the equilibrium will shift <= <= <= when the temperature is increased on an equilibrium that  produces heat

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b) N2 (g) + 3 H2 (g) + heat ↔ 2 NH3 (g)

K = [NH3}2 / [N2] [H2]3

K = [0.0114}2 / [0.103] [0.240]3

K = 1.30 / 5.93e-3

K = 219

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

(2) the equilibrium will shift => =>  => when pressure is increased, on equilibriums that more moles of gases as stasrting materials

(3) no body is underlined , but 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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c) H2 (g) + Cl2 (g) ↔ 2 HCl (g) + heat

K = [0.784]2 /[0.21] [0.22]

K = 13.3

(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) no body is underlined, but 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

Answer 2

(a) Ke = [N2]^2[H2O]^6 / [NH3]^4[O2]^3

Ke = 0.0794^2 * 0.10^6 / 0.10^7

Ke = 0.0794^2/0.10  =  6.3x10^-2

decrease temperature: shift right

increase pressure: shift left

nothing underlined

increase temperature: shift left