Skip to main content
Ch.15 - Chemical Equilibrium
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoMcMurry 8th EditionCh.15 - Chemical EquilibriumProblema 144
Capitolo 15, Problema 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%?

Guida verificata passo dopo passo
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 \(K_c\).

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
3m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

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.
Video consigliato:
Percorso guidato
00:44
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.
Video consigliato:
Percorso guidato
03:20
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.
Video consigliato:
Percorso guidato
07:35
Calculate Concentration of the Basic Form
Pratica correlata
Domanda del libro di testo
In automobile catalytic converters, the air pollutant nitric oxide is converted to nitrogen and oxygen. Listed in the table are forward and reverse rate constants for the reac- tion 2 NO1g2 ∆ N21g2 + O21g2. Temperature (K) kf1M — 1 s-12 kr1M-1 s — 12 1400 0.29 1.1 * 10-6 1500 1.3 1.4 * 10-5 Is the reaction endothermic or exothermic? Explain in terms of kinetics.
429
views
Domanda del libro di testo

Refining petroleum involves cracking large hydrocarbon molecules into smaller, more volatile pieces. A simple example of hydrocarbon cracking is the gas-phase thermal decomposition of butane to give ethane and ethylene: (a) Write the equilibrium constant expressions for Kp and Kc.

322
views
Domanda del libro di testo

Refining petroleum involves cracking large hydrocarbon molecules into smaller, more volatile pieces. A simple example of hydrocarbon cracking is the gas-phase thermal decomposition of butane to give ethane and ethylene: (c) A sample of butane having a pressure of 50 atm is heated at 500 °C in a closed container at constant volume. When equilibrium is reached, what percentage of the butane has been converted to ethane and ethylene? What is the total pressure at equilibrium?

329
views
Domanda del libro di testo
Heavy water, symbolized D2O 1D = 2H2 finds use as a neutron moderator in nuclear reactors. In a mixture with ordinary water, exchange of isotopes occurs according to the following equation: H2O + D2O ∆ 2 HDO Kc = 3.86 at 298 K When 1.00 mol of H2O is combined with 1.00 mol of D2O, what are the equilibrium amounts of H2O, D2O, and HDO (in moles) at 298 K? Assume the density of the mixture is constant at 1.05 g>cm3.
285
views
Domanda del libro di testo
Given the Arrhenius equation, k = Ae-Ea>RT, and the rela- tion between the equilibrium constant and the forward and reverse rate constants, Kc = kf>kr, explain why Kc for an exothermic reaction decreases with increasing temperature.
407
views