Equilibrium Expressions in Reactions

The video tutorial covers homogeneous and heterogeneous equilibria, explaining how the equilibrium constant is calculated based on the concentrations of reactants and products. It highlights that pure solids and liquids are not included in the equilibrium constant calculation. An example of carbon dioxide reacting with graphite is provided, demonstrating that the equilibrium composition remains the same regardless of the amount of solid carbon present. The tutorial also includes practice exercises for writing equilibrium expressions, emphasizing the exclusion of solids, pure substances, and solvents from these expressions.

What is the main difference between homogeneous and heterogeneous equilibria?

• All reactants and products are in the same phase in homogeneous equilibria.

• Heterogeneous equilibria involve only gases.

• Homogeneous equilibria involve solids and liquids only.

• Heterogeneous equilibria do not have an equilibrium constant.

Why are pure solids and liquids not included in the equilibrium constant calculation?

• Their concentrations do not change during the reaction.

• They are not part of the reaction.

• They react too quickly.

• Their concentrations are too high.

In the reaction between carbon dioxide and graphite, what remains constant regardless of the amount of graphite?

• The temperature of the reaction.

• The pressure in the chamber.

• The equilibrium composition of the gas phase.

• The amount of carbon monoxide produced.

What is excluded from the equilibrium expression in a reaction involving calcium carbonate and calcium oxide?

• Neither calcium carbonate nor calcium oxide.

• Both calcium carbonate and calcium oxide.

• Calcium oxide only.

• Calcium carbonate only.

In a reaction involving copper and silver ions, which substances are included in the equilibrium expression?

• Silver ions and water.

• Copper ions and silver ions.

• Copper ions and water.

• Copper and silver ions.

For a reaction with only gases, what should be included in the equilibrium expression?

• Only the gases with the highest concentration.

• All gases involved.

• Only the products.

• Only the reactants.

In the equilibrium expression for a reaction, why is water often excluded?

• It is not part of the reaction.

• It reacts too slowly.

• It is a solvent.

• It is a solid.

What is the role of the geometric coefficient in an equilibrium expression?

• It determines the temperature of the reaction.

• It is used as an exponent for concentrations in the expression.

• It affects the concentration of reactants.

• It is used to balance the chemical equation.

In the reaction involving iron oxide and hydrogen, which substances are excluded from the equilibrium expression?

• Iron and water.

• Iron oxide and hydrogen.

• Iron oxide and iron.

• Hydrogen and water.

What is the exponent of H2O in the equilibrium expression for the reaction involving iron oxide and hydrogen?

• 2

• 4

• 5

• 3