Equilibrium Unit Review

 The reaction 2SO_{2 (g)} + O_{2 (g)} ↔ 2SO_{3 (g)} has reached a state of equilibrium. 

Why is this considered to be a dynamic system?

• The K_eq value for the system is continuing to change.

• The forward and reverse reactions continue to occur at the same rate.

• The forward and reverse reactions have stopped.

• There are equal quantities of reactants and products.

Consider the following equilibrium system:

H₂S _(g) + I_{2 (s)} ↔ 2HI_(g) + S_(s)

Which of the following equations correctly represents the concentration of H₂S _(g) at equilibrium?

• a

• b

• c

• d

Which statement concerning a saturated solution at equilibrium is true?

• Neither dissolving nor crystallizing is occurring.

• The concentrations of solute and solvent are always equal.

• The mass of dissolved solute is always greater than the mass of solvent.

• The rate of dissolving equals the rate of precipitation.

Consider the following solution equilibrium:

                        MgCO_{3 (s)}  ↔  Mg²⁺_(aq) + CO₃^2-_(aq)

            Which of the following changes would shift equilibrium to the left?

• adding K₂CO_{3 (s)}  

• adding MgCO_{3 (s)}

• removing CO₃^2-_(aq)               

• increasing the pressure

Which of the following statements about K_eq is true?

• The equilibrium constant is equal to 6.02 x 10²³.

• The equilibrium constant is greater than 1 when products are favoured at equilibrium.

• The equilibrium constant is less than 1 when products are favoured at equilibrium.

• Solids and liquids are included in the expression.

Which of the following stresses will NOT cause a shift in equilibrium?

H_2(g) + I_2(g) ⇄ 2HI_(g) + energy

• decrease [I₂]

• increase [H₂]

• decrease volume

• increase temperature

Which of the options below indicate that the reactants are favored in an equilibrium system?

• Keq is zero

• Keq is less than 1

• Keq is very large

• Keq is greater than 1

Choose the equilibrium which will shift right with a decrease in pressure but left with a

decrease in temperature.

• a

• b

• c

• d

• e

All chemical equilibriums must have

• Keq = 1 

• [reactants]=[products]

• forward rate = reverse rate

• mass of reactants = mass of products

The value of Keq changes when:

• a catalyst is added.

• the temperature changes.

• the surface area changes.

• the concentration of reactants changes.