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) ΔHrxn = −25 kJ The temperature is increased. (select one for each situation)

1. The volume of the reaction vessel in incresed.

2.Water is added to the reaction.

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

4. A catalyst is added.

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

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.

Answer 1

A(g) + 2B(aq) → 2C(g) ΔHrxn = −25 kJ

1. The volume of the reaction vessel in incresed. --> if V increases, P decreases, then this favours most moles of gas formation, that is; C since there arte 2 mole of gas, the reaction goes FORWARD, that is C

2.Water is added to the reaction. --> water will dilute B; therefore, the shift goes to REACTANTS; in the REVERSE reaction, choose A

3. Solid B is added to the flask, which subsequently dissolves in the aqueous solution increasing the concentration of B. If B increases concnetration, the shift goes to PRODUCTs, to the FORWARD direction, therefore, choose C

4. A catalyst is added. Choose B, there are no effects in equilibirum with catalysts

5. Helium is pumped into the reaction flask increasing the total pressure of the system. IF He increases P, then this favours the least mol formation, that is, the reactants, the REVERSE reaction, choose A