Chapter 16: Chemical Equilibrium

Question 1

reversible

Answer 1

As applied to a reaction, describes the ability to proceed in either the forward or the reverse direction.

Question 2

dynamic equilibrium

Answer 2

For a chemical reaction, it is the condition in which the rate of the forward reaction equals the rate of the reverse reaction.

Question 3

equilibrium constant (K)

Answer 3

The ratio, at equilibrium, of the concentrations of the products of a reaction raised to their stoichiometric coefficients to the concentrations of the reactants raised to their stoichiometric coefficients.

K = [C]^c[D]^d/ [A]^a[B]^b

[x] = molar concentration of x

It says nothing about how fast a reaction reaches equilibrium, only how far the reaction has proceeded once equilibrium is reached.

Question 4

law of mass action

Answer 4

The relationship between the balanced chemical equation and the expression of the equilibrium constant.

Question 5

Summarize the significance of the equilibrium constant

Answer 5

• K<<1 Reverse reaction is favored; forward reaction does not proceed very far. More reactants than products when equilibrium is reached. High concentrations of reactants and low concentrations of products.
• K>>1 Forward reaction is favored; forward reaction proceeds essentially to completion. Numerator is larger than denominator. High concentrations of products, low for reactants.
• K≈1 Neither direction is favored; forward reaction proceeds about halfway.