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Ch.15 - Chemical Equilibrium
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145당신이 사용하는 게 아니라요?교과서 변경
모든 교과서McMurry 8th EditionCh.15 - Chemical Equilibrium문제 144
15장, 문제 144

Vinegar contains acetic acid, a weak acid that is partially dissociated in aqueous solution: CH3CO2H1aq2 ∆ H+ 1aq2 + CH3CO-1aq2 (b) What is the value of Kc if the extent of dissociation in 1.0 M CH3CO2H is 0.42%?

검증된 단계별 안내
1
Identify the initial concentration of acetic acid, \([CH_3CO_2H] = 1.0\, M\).
Calculate the concentration of dissociated acetic acid using the extent of dissociation: \(0.42\%\) of \(1.0\, M\).
Determine the concentrations of \(H^+\) and \(CH_3COO^-\) ions, which are equal to the concentration of dissociated acetic acid.
Write the expression for the equilibrium constant \(K_c\) for the dissociation: \(K_c = \frac{[H^+][CH_3COO^-]}{[CH_3CO_2H]}\).
Substitute the equilibrium concentrations into the \(K_c\) expression and solve for \(K_c\).

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주요 개념

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Weak Acids and Dissociation

Weak acids, like acetic acid, do not completely dissociate in solution. Instead, they establish an equilibrium between the undissociated acid and its ions. The extent of dissociation indicates how much of the acid has converted to ions, which is crucial for calculating equilibrium constants.
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ICE Charts of Weak Acids

Equilibrium Constant (Kc)

The equilibrium constant, Kc, quantifies the ratio of the concentrations of products to reactants at equilibrium for a given reaction. For the dissociation of acetic acid, Kc can be calculated using the concentrations of H+ and CH3CO- ions relative to the undissociated CH3CO2H, reflecting the extent of the reaction.
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Equilibrium Constant Expressions

Calculating Concentrations from Extent of Dissociation

To find Kc, one must first determine the concentrations of the species at equilibrium based on the initial concentration and the extent of dissociation. For a 1.0 M solution with 0.42% dissociation, the concentrations of H+ and CH3CO- can be calculated, allowing for the determination of Kc using the equilibrium expression.
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Calculate Concentration of the Basic Form
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