5.6 EQUILIBRIA

Question 1

Which way in a reversible reaction, does the enthalpy change refer to

Answer 1

The forwards reaction

Question 2

Define dynamic equilibrium

Answer 2

In a sealed container, when the forawards and backwards reactions are happening at the same rate, and concentrations of reactants and products remain unchanged

Question 3

Which way will equalibrium shift when a substance is added

Answer 3

• Excess needs to be removed
• Equalibrium shifts other side
• Because forwards/backwards reaction uses it up

Question 4

Which way will equalibrium shift when you remove a substance

Answer 4

• The product needs to be replaced
• The equalibrium shifts to the same side
• The forwards/backwards reaction creates the product

Question 5

Which way will equalibrium shift when pressure is increased

Answer 5

• We need to lower the pressure
• The equalibirum shifts left/right
• As there are fewer moles on the left/right

Question 6

Which way will equalibrium shift when pressure is decreased

Answer 6

• We need to increase the pressure
• The equalibirum will shift left/right
• As there are more moles on the left/right

Question 7

When there are no moles of gas on either side, or there are equal numbers of moles of gas on both sides, what happens to equalibirum when gas pressure is changed

Answer 7

No effect

Question 8

Which way will equalibrium shift when temperature is increased

Answer 8

• We need to lower the temperature
• The equalibrium will shift left/right
• As the backwards/forwards reaction is endothermic

Question 9

Which way will equalibrium shift when temperature is decreased

Answer 9

• We need to increase temperature
• Equalibirum shifts left/right
• As forwards/backwards is exothermic

Question 10

What effect does catalysts have on equalibrium shifts

Answer 10

They have no effect - they increase forwards and backwards reaction