Chemical Equilibrium

In the oxidation reaction

CaO (s) +H2O (l) ↽−−⇀Ca(OH)₂ (s) + heat

Lowering the temperature will favor

• forward reaction

• backward reaction

• dynamic equilibrium

• all of the above

Why is equilibrium called a dynamic state?

• Chemists try to convert as much reactants as possible into products.

• The reactions at equilibrium continue to take place once equilibrium is established.

• The products of a forward reaction are favored, so equilibrium lies to the right.

• All chemical reactions are considered to be reversible under suitable conditions.

At what time (in seconds) is equilibrium established?

• 0 second

• 1 second

• 5 seconds

• 10 seconds

Le Chaltelier's Principle states that if a chemical system at equilibrium is stressed,

• the system will adjust to increase the stress

• the system will adjust to reduce the stress

• the system will not adjust

An exothermic reaction is allowed to reach equilibrium. If heat energy is then removed, the equilibrium will shift

• toward the middle

• toward the reactant side

• toward the product side

Which of the following is NOT true at equilibrium?

• The forward and reverse reactions proceed at the same rate.

• The concentrations of reactants and products do not change.

• The concentration of the reactants is equal to the concentration of the products.

• The forward and reverse reactions continue to occur.

For the reaction...

SO_2(g) + O_2(g) <−> SO_3(g)

If the concentration of SO_2(g) is increased, the equilibrium of the reaction will ___________.

• shift to the left

• shift to the right

• no shift

For the reaction...

SO_2(g) + O_2(g) <−> SO_3(g)

If the equilibrium shifts to the right, the concentration of O_2(g) will ___________.

• increase

• decrease

• remain the same

When writing an endothermic reaction, heat energy is stated as

• product

• catalyst

• reactant

For the reaction...

N_{2 (g)} + 3 H_{2 (g)} <−> 2 NH_{3 (g)}

If the pressure in the system is increased, the reaction will __________________.

• shift to the left

• shift to the right

• not shift