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Honors Chemistry Reading Guide
Chemical Equilibrium
Chapter 16
Section 1: The Nature of Chemical Equilibrium
Define the following terms:
reversible reaction:
chemical equilibrium:
equilibrium constant:
What is meant by the term “dynamic equilibrium”?
What is meant when it is stated that an equilibrium system “lies to the right” or “lies to the left”?
As a reaction progresses toward equilibrium, what happens to the rate of the forward reaction? What
happens to the rate of the reverse reaction?
What is true about the rates of the forward and reverse reaction AT equilibrium?
What is true about the concentrations of the reactants and products at equilibrium?
What does the value of Kc indicate about a chemical system at equilibrium?
WHY are pure solids and liquids omitted from a Kc expression?
HOW is the value of Kc for a particular system determined?
Given that values of K do not depend on initial concentrations of reactants or products, what can change
the value of Kc for a given reaction system?
Section 2: Shifting Equilibrium
Define the following term:
common–ion effect:
Identify three ways that a chemical equilibrium can be disturbed.
What kind of equilibrium systems are affected by a change in pressure?
How does the addition of a noble gas, such as helium, affect the position of a gaseous equilibrium?
How does the addition of a solid to a heterogeneous reaction affect the equilibrium position?
Why does a change in temperature change the value Kc, while a change in pressure or concentration does
not change its value?
Will increasing temperature of a system at equilibrium favor the exothermic or endothermic reaction?
What is the effect of adding a catalyst to a system at equilibrium?
Identify three conditions under which some reactions go “to completion”?
Why does the addition of NaCl to a saturated solution of AgCl decrease solubility of the AgCl?
Predict the effect of each of the following on the indicated equilibrium system by indicating the direction
of equilibrium shift (forward, reverse or neither).
H2 (g) + Cl2 (g)  2 HCl (g)
o
addition of Cl2
o
removal of HCl
o
increased pressure
o
decreased temperature
o
removal of H2
o
decreased pressure
o
addition of a catalyst
o
increased temperature
*NOTE: you are NOT responsible for Section 3!
Section 4: Solubility Equilibrium
Define the following term:
solubility product constant:
Explain why a saturated solution is not necessarily a concentrated solution.
What “rule of thumb” is used to distinguish between soluble and slightly soluble substances?
Explain the difference between “solubility” and “solubility product constant”?
How can the Ksp be used to find the solubility of a substance?
Identify the most soluble and the least soluble salt and their Ksp value in Figure 4.1
most soluble
least soluble
How can a Ksp be used to predict precipitation formation?