# Worksheet: Types of Equilibrium

In this worksheet, we will practice classifying equilibria as static or dynamic and as homogeneous or heterogeneous.

Q1:

The following reaction occurs when a burner on a gas stove is lit. Which of the following statements is an accurate description of this reaction?

• AAn equilibrium is not established because the rate of the forward reaction is much greater than the rate of the reverse reaction.
• BAn equilibrium is not established because the reaction is highly exothermic, preventing the temperature from reaching a constant value.
• CAn equilibrium is not established because the gas stove is not a closed system and the product gases can escape.
• DAn equilibrium is established because the reaction does not alter the number of moles of gas in the system.
• EAn equilibrium is established because carbon dioxide and water are already present in the air.

Q2:

If a reaction is reversible, when can it be said to have reached equilibrium?

• AWhen the reactants and the products have equal concentrations
• BWhen the concentrations of the reactants and products change with time
• CWhen the rates of the forward and reverse reactions are equal
• DWhen the concentrations of the products are equal to the standard value, typically 1 M
• EWhen the reactants are fully consumed

Q3:

Which of the following is the correct definition of a reversible reaction?

• AThe forward reaction and the reverse reaction occur at the same rate.
• BThe reaction can proceed in both the forward and reverse directions.
• CA second reaction converts the products of the reaction back to reactants, resulting in a cyclic process.
• DIf you reverse the flow of time, the reaction will undo itself.
• EThe reaction can be undone with the right catalyst.

Q4:

Under standard conditions, a sealed container of bromine consists of a liquid phase in equilibrium with a gaseous phase. Why would it be impossible to establish an equilibrium between and if the container were not a closed one?

• AIn an open system, the rate of condensation is limited by diffusion of out of the container.
• BIn an open system, the container would empty due to rapid vaporization of .
• CIn an open system, it is always more favorable for the material to exist in the gas phase.
• DIn an open system, the rate of condensation is limited by variation of the boiling point with the liquid mass.
• EIn an open system, the bromine would be consumed by reaction with air before the phases could equilibrate.

Q5:

At the boiling point of a liquid, which of the following conditions is satisfied?

• AVapor pressure equals the liquid surface tension.
• BThe rate of evaporation equals the rate of convection.
• CThe rate of evaporation equals the rate of condensation.
• DThe free energies of vaporization and condensation are equal in magnitude.
• EVapor pressure equals atmospheric pressure.

Q6:

For at and 1 atm and at and 1 atm, which of the following quantities must be equal for the two phases?

• AThe molar Gibbs free energy (Gm)
• BThe molar volume (Vm)
• CThe molar enthalpy (Hm)
• DThe molar entropy (Sm)

Q7:

Heat is added to a block of ice in a bath of liquid water at . A student records the temperature of the ice and the mass of liquid water . The system remains at thermal equilibrium and ice remains at the end of the process. Which quantities do not change?

• ABoth and