Equilbrium

Question 1

IRREVRSIBLE Vs REVERSIBLE reactions

Answer 1

IRREVERSIBLE:
- Goes in one direction
- Goes to completion
- Shown by arrow pointing from reactants
to products
- The products do not convert back into the original reactants
- E.G decomposition of hydrogen peroxide

REVERSIBLE:
- The reactants are converted to the products at the same time as the products are converted to reactants
- The reversible sign shows the reaction is in EQUILBRIUM

Question 2

DNAMIC EQUILBRIUM ~ Definition

Answer 2

DYNAMIC EQULIBRIUM:

• the rate of the forward reaction is equal to the rate of the backward reaction
• the concentrations of the reactants and products remain constant

Question 3

DYNAMIC EQUILBRIUM ~ Explained

Answer 3

Occurs when a reversible reaction takes place in a CLOSED SYSTEM:

• neither the products or reactants can enter or leave
• the temperature, pressure or concentration of the reactants and products remains unchanged
• The reactants are forming the products as FAST AS the products are forming the reactants

Question 4

The POSITION of equilibrium

Answer 4

• Indicates the EXTENT of the reaction
• The PROPORTION of products to reactants in the equilibrium mixture

Question 5

Le Chatelier’s Principle

Answer 5

According to le Chatelier’s principle:

’ When a system in equilibrium is subjected to an external change , the system readjusts itself to MINIMISE the effect of tat change’

The position of equilibrium shifts to CANCEL OUT any changes in:
- Temperature
- Pressure
- Concentration

Question 6

Gas Pressure

Answer 6

Pressure = Force/Area

• The greater number of MOLES of a reactant or product in an equilibrium mixture…
• the greater the gas pressure it exerts

Question 7

TEMPERATURE ~ effect on equilibrium reaction

Answer 7

INCREASE TEMPERATURE:
- Equilibrium moves in the ENDOTHERMIC
direction
- REDUCES the temperature of the system
- MINIMISES the change

DECREASE TEMPERATURE:
- Equilibrium moves in the EXOTHERMIC direction
- INCREASES the temperature of the system
- MINIMISES the change

Question 8

CONCENTRATION ~ effect on equilibrium reaction

Answer 8

INCREASE CONCENTRATION OF REACTANTS:
- Equilibrium moves to the RIGHT
- REDUCES concentration of reactants
- MINIMISES the change

DECREASE CONCENTRATION OF REACTANTS:
- Equilibrium moves to the LEFT
- INCREASES concentration of reactants
- MINIMISES the change

INCREASE CONCENTRATION OF PRODUCTS:
- Equilibrium moves to the LEFT
- REDUCES concentration of products
- MINIMISES the change

DECREASE CONCENTRATION OF PRODUCTS:
- Equilibrium moves to the RIGHT
- INCREASES concentration of products
- MINIMISES the change

Question 9

PRESSURE ~ effect on equilibrium reaction

Answer 9

INCREASE PRESSURE:
- Equilibrium moves to the side with FEWER
MOLES
- DECREASES the pressure of the system
- MINIMISES the change

DECREASE PRESSURE:
- Equilibrium moves to the side with MORE
MOLES
- INCREASES the pressure of the system
- MINIMISES the change

Only effects reactions that have BOTH:

• Species in GASEOUS STATE
• Different number of MOLES on either side
  of the reaction

Question 10

CATALYST ~ effect on equilibrium reaction

Answer 10

• Provides an alternative pathway with a lower activation energy
• INCREASE THE RATE of BOTH the forward and backward reaction TO THE SAME EXTENT
• The equilibrium is ATTAINED FASTER
• NO EFFECT ON POSITION OF EQUILBRIUM~ remains the same