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O-000 Extended 7:50 PM 61% , 6 Question 1 Cyclohexane (a liquid) undergoes isome

ID: 542964 • Letter: O

Question

O-000 Extended 7:50 PM 61% , 6 Question 1 Cyclohexane (a liquid) undergoes isomerization in the presence of aluminum chloride to form methylcyclopentane (also a liquid). The equilibrium constant for this reaction is 0.143 at 25°C Calculate the equilibrium concentrations of the reactant and the product if we start with 0.200 M cyclohexane and 0.100 M methylcyclopentane Question 2 Working again with our old friend, the equilibrium system consisting of hydrogen and iodine as reactants and hydrogen iodide as product. .. At 1000 K, the equilibrium constant is 29.1 What are the equilibrium concentrations of all the reactants and products if the systenm originally contained only [HI] 10.0 M? Bonus Questions What is the purpose of the aluminum chloride in Question 1? Write the rate law for the reaction in Question 1 What effect will the aluminum chloride have on

Explanation / Answer

1) The equilibrium reaction is given as

Cyclohexane (l) <=====> Methylcyclopentane (l)

Keq = [Methylcyclopentane]/[Cyclohexane] = 0.143

Set up the ICE chart as below.

Cyclohexane (l) <======> Methylcyclopentane (l)

initial                            0.200 M                                0.100 M

change                              -x                                           +x

equilibrium                   (0.200 – x)                            (0.100 + x)

Plug in values in the Keq expression

Keq = (0.100 + x)/(0.200 – x)

====> 0.143 = (0.100 + x)/(0.200 – x)

====> 0.143*(0.200 – x) = 0.100 + x

====> 0.0286 – 0.143x = 0.100 + x

====> 0.0286 – 0.100 = x + 0.143x

====> -0.0714 = 1.143x

====> x = -0.0714/1.413 = -0.0505

The value of x turns out to be negative since we have the product to start with and hence, the equilibrium will favor the reverse reaction. The equilibrium concentrations are given as

[Cyclohexane] = [0.200 – (-0.0505)] M = 0.2505 M (ans).

[Methylcyclopentane] = [0.100 + (-0.0505)] M = 0.0495 M (ans).