Question

Based on Le Chatelier's Principle in which direction will the following reaction proceed if it is already at equilibrium given the following change in conditions.

A(g) + 2B(aq) → 2C(g) ΔH_rxn = −25 kJ

Answer Choices

A.Reaction will proceed in the reverse direction to reestablish equilibrium.
B.The reaction is still at equilibrium and will not change.
C.Reaction will proceed in the forward direction to reestablish equilibrium.

Questions

-The temperature is increased.

-The volume of the reaction vessel in incresed.

-Water is added to the reaction.

-Solid B is added to the flask, which subsequently dissolves in the aqueous solution increasing the concentration of B.

-A catalyst is added.

-Helium is pumped into the reaction flask increasing the total pressure of the system.

Answer 1

A(g) + 2B(aq) → 2C(g) ΔHrxn = −25 kJ

-The temperature is increased. --> since this is exothermic, If T is increased, it favours the REVERSE direction, choose A

-The volume of the reaction vessel in incresed. --> mol of gases in reactants = 1 and mol of gases in products = 2; increasing the volume, decreases pressure, therefore, it favours the most gases phase; that is, the products, the shift goes to the FORWARD direction, choose C

-Water is added to the reaction. -->if water is added, the concnetration of B decreases, is B decreases, then the shift goes to reactants, that is, REVERSE, choose A

-Solid B is added to the flask, which subsequently dissolves in the aqueous solution increasing the concentration of B.--> as before, increasing B concnentration will favourproduct formation, that is FORWARD reaction, choose C

-A catalyst is added. Catalyst will never change th eequilibrium; it only changes rates (time)

-Helium is pumped into the reaction flask increasing the total pressure of the system. If P increases, then this favours to the LEAST number of gas moles, this is reactants, therefore shift goes REVERSE, choose A