Calculating equilibrium concentrations when the net reaction proceeds in reverse

Concentration (M)

[XY] [X] [Y]

initial: 0.200 0.300 0.300

change: + x - x - x

equilibrium: 0.200+x 0.300-x 0.300-x

Based on a Kc value of 0.170 and the data table given, what are the equilibrium concentrations of XY, X, and Y, respectively?

Question

Ashlyn

Chemistry

13 November, 19:33

Calculating equilibrium concentrations when the net reaction proceeds in reverse

Concentration (M)

[XY] [X] [Y]

initial: 0.200 0.300 0.300

change: + x - x - x

equilibrium: 0.200+x 0.300-x 0.300-x

Based on a Kc value of 0.170 and the data table given, what are the equilibrium concentrations of XY, X, and Y, respectively?

+3

Answers (1)

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Madilyn Henderson · Answer 1

Kc = [XY] / [X][Y]

0.17 = (0.2 + x) / (0.3 - x) (0.3-x)

0.17 (0.3 - x) ² = 0.2 + x

0.17 (0.09 - 0.6x + x²) = 0.2 + x

0.0153 - 0.102x + 0.17x² = 0.2 + x

0.17x² - 1.102x + 0.053 = 0

Solving the quadratic:

x = 0.048

Thus, equilibrium concentrations:

[XY] = 0.2 + 0.048 = 0.248

[X] = 0.3 - 0.048 = 0.252

[Y] = 0.3 - 0.048 = 0.252