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Acetic acid, CH3CO2H, reacts with ethanol, C2H5OH, to form water and ethyl acetate, CH3CO2C2H5. The equilibrium constant for this reaction with dioxane as a solvent is 4.0. What are the equilibrium concentrations for a mixture that is initially 0.15 M in CH3CO2H, 0.15 M in C2H5OH, 0.40 M in CH3CO2C2H5, and 0.40 M in H2O?

Respuesta :

Explanation:

The initial concentrations for a mixture :

Acetic acid at equilibrium = 0.15 M

Ethanol at equilibrium = 0.15 M

Ethyl acetate at equilibrium = 0.40 M

Water at equilibrium = 0.40 M

[tex]CH3COOH + C_2H_5OH\rightleftharpoons CH_3CO_2C_2H_5+H_2O[/tex]

Initially:

0.15 M            0.15 M            0.40 M   0.40 M

At equilibrium

(0.15-x)M       (0.15-x) M     (0.40+x) M   (0.40+x) M

The equilibrium constant is given by expression

[tex]K_c=\frac{[CH_3CO_2C_2H_5][H_2O]}{[CH_3COOH][C_2H_5OH]}[/tex]

[tex]4.0=\frac{(0.40-x)\times (0.40-x)}{(0.15+x)\times (0.15+x)}[/tex]

Solving for x:

x = 0.0333

The equilibrium concentrations for a mixture :

Acetic acid at equilibrium = (0.15-x)M = (0.15-0.033) M = 0.117 M

Ethanol at equilibrium = (0.15-x)M = (0.15-0.033) M = 0.117 M

Ethyl acetate at equilibrium = (0.40+x)M = (0.40+0.033) M = 0.433 M

Water at equilibrium = (0.40+x)M = (0.40+0.033) M = 0.433 M

dsdrajlin

For the reaction between acetic acid and ethanol to form water and ethyl acetate, the concentrations at equilibrium are:

  • [CH₃CO₂H] = [C₂H₅OH] = 0.18 M
  • [CH₃CO₂C₂H₅] = [H₂O] = 0.37 M

What is chemical equilibrium?

In a chemical reaction, chemical equilibrium is the state in which both the reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system.

  • Step 1: Write the balanced equation.

CH₃CO₂H(aq) + C₂H₅OH(aq) ⇄ CH₃CO₂C₂H₅(aq) + H₂O(aq)

  • Step 2: Determine if the system is at equilibrium.

We will calculate the reaction quotient (Q).

Q = [CH₃CO₂C₂H₅] [H₂O] / [CH₃CO₂H] [C₂H₅OH]

Q = 0.40² / 0.15² = 7.11

Since Q > K, the system will shift towards the reactants to attain equilibrium.

  • Step 3: Make an ICE chart.

       CH₃CO₂H(aq) + C₂H₅OH(aq) ⇄ CH₃CO₂C₂H₅(aq) + H₂O(aq)

I            0.15                   0.15                       0.40                  0.40

C            +x                       +x                          -x                       -x

E         0.15 + x              0.15+x                   0.40-x                0.40-x

The equilibrium constant (K) is:

K = [CH₃CO₂C₂H₅] [H₂O] / [CH₃CO₂H] [C₂H₅OH]

K = (0.40-x)² / (0.15+x)² = 4.0

x = 0.033

The concentrations at equilibrium are:

[CH₃CO₂H] = [C₂H₅OH] = 0.15 + x = 0.15 + 0.033 = 0.18 M

[CH₃CO₂C₂H₅] = [H₂O] = 0.40 - x = 0.40 - 0.033 = 0.37 M

For the reaction between acetic acid and ethanol to form water and ethyl acetate, the concentrations at equilibrium are:

  • [CH₃CO₂H] = [C₂H₅OH] = 0.18 M
  • [CH₃CO₂C₂H₅] = [H₂O] = 0.37 M

Learn more about chemical equilibrium here: https://brainly.com/question/5081082

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