Reversible reactions, le chatlier's principle and equillibria

What is le chatlier’s principle?

A system at equillibrium will shift the position of equillibrium to oppose a change imposed upon the system.

What is dynamic equillbrium?

When a system reaches equillibrium, the forward and backward reaction occurs at equal rates in a closed system. But the concentration of reagents and products remains the same

What is a closed system?

In a closed system, nothing is added or taken away from the reaction mixture.

What is exothermic?

Reaction releasing energy

What is endothermic?

Reaction absorbing energy

If the pressure is increased what happens?

The equillbrium will shift to the side with the least amount of molecules / moles to oppose the change and help use up the excess molecules / moles.

If the pressure is decreased what happens?

The equillibrium will shift to the side with most amount of molecules / moles to oppose the change and try make more particles to increase the pressure.

If the forward reaction is exothermic and temperature increases, what happens?

The equillibrium shifts to the left hand side, the endothermic side helps to absorb more energy therefore opposing the change imposed. Yield will decrease.

If the forward reaction is endothermic and temperature increases, what happens?

The equillibrium shifts to the right hand side, the endothermic side helps to absorb more energy therefore opposing the change imposed. Yield will increase

If the forward reaction is exothermic and temperature decreases, what happens?

The equillibrium shifts to the right hand side, the exothermic side helps to release more energy therefore opposing the change imposed. Yield will increase

If the forward reaction is endothermic and temperature decreases, what happens?

The equillibrium shifts to the left hand side, the exothermic side helps to release more energy therefore opposing the change imposed. Yield is decreased.

If the change in heat energy of the system is negative?

The forward reaction is exothermic

If the change in heat energy of the system is positive?

The forward reaction is endothermic

When exothermic and temperature increases?

Yield decreases

When exothermic and temperature decreases?

Yield increases

When endothermic and temperature increases?

Yield increases

When endothermic and temperature decreases?

Yield decreases

Larger volume of gas on RHS, pressure increases?

Yield decreases

Larger volume of gas on RHS, pressure decreased?

Yield increases

Smaller volume of gas on RHS, pressure increased?

Yield increases

Smaller volume of gas on RHS, pressure decreased?

Yield decreased

If we add more of A or B what happens?

Shifts to the left hand side to oppose the change and use up excess A or B, producing more C + D

If we add more of C or D what happens?

Shifts the the right hand side to oppose the change and use up excess C or D, producing more A or D