Chapter 6.1 And 6.2 - Equilibrium

Question 1

Define the term dynamic equilibrium

Answer 1

The rate of forward reaction is equal to the rate of backward reaction, the concentration of the product and reactants do not change

Question 2

Give an essential condition for an equilibrium mixture

Answer 2

Occurs in a closed system,
Must be a reversible reaction

Question 3

State le chateliers princiciple

Answer 3

-If a system at equilibrium is disturbed the equilibrium moves in the direction that tends to reduce the disturbance

-an equilibrium opposes change

Question 4

Suggest and explain why an industrial chemist may use high pressure for the production of hydrogen from CH4 + H2O <=> CO + 3H2

Answer 4

The high pressure increases the collision frequency, increasing the rate of reaction

Question 5

What effect would increasing the concentration of a reactant have on the position of the equilibrium ?

Answer 5

If you increase the concentration of a reactant, the equilibrium tries to get rid of the extra reactant. It does this by making more product so equilibrium shifts to the right

Question 6

What effect would increasing the concentration of a product have on the position of the equilibrium ?

Answer 6

If you increase the concentration of the product the equilibrium tries to remove the extra product. This makes the reverse reaction to faster so equilibrium shifts to the left

Question 7

What effect would increasing the pressure have on the position of the equilibrium ?

Answer 7

Increasing the pressure shifts the equilibrium to the side with fewer gas molecules. This reduces pressure

Question 8

What effect would decreasing the pressure have on the position of the equilibrium ?

Answer 8

Decreasing the pressure shifts the equilibrium to the sides with more gas molecules. This raises the pressure again

Question 9

What effect would increasing the temperature have on the position of the equilibrium ?

Answer 9

Increasing the temperature means adding heat, the equilibrium shifts in the endothermic direction to absorb this heat

Question 10

What effect would decreasing the temperature have on the position of the equilibrium ?

Answer 10

Decreasing the temperature means removing heat, this equilibrium shifts in the exothermic direction to produce more heat

Question 11

Summery of the reversible reaction:

Answer 11

Forward reaction exothermic:
temperature ↑ means yield ↓.

Forward reaction endothermic:
temperature ↑ means yield ↑.

Fewer molecules on the right hand side of the equation:
pressure ↑ means yield ↑.

Question 12

Give two features of a reaction at equilibrium (2)

Answer 12

-concentration of reactants and products remain constant
-rate of forward reaction = rate of backward reaction