5.6 EQUILIBRIA Flashcards
Which way in a reversible reaction, does the enthalpy change refer to
The forwards reaction
Define dynamic equilibrium
In a sealed container, when the forawards and backwards reactions are happening at the same rate, and concentrations of reactants and products remain unchanged
Which way will equalibrium shift when a substance is added
- Excess needs to be removed
- Equalibrium shifts other side
- Because forwards/backwards reaction uses it up
Which way will equalibrium shift when you remove a substance
- The product needs to be replaced
- The equalibrium shifts to the same side
- The forwards/backwards reaction creates the product
Which way will equalibrium shift when pressure is increased
- We need to lower the pressure
- The equalibirum shifts left/right
- As there are fewer moles on the left/right
Which way will equalibrium shift when pressure is decreased
- We need to increase the pressure
- The equalibirum will shift left/right
- As there are more moles on the left/right
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
No effect
Which way will equalibrium shift when temperature is increased
- We need to lower the temperature
- The equalibrium will shift left/right
- As the backwards/forwards reaction is endothermic
Which way will equalibrium shift when temperature is decreased
- We need to increase temperature
- Equalibirum shifts left/right
- As forwards/backwards is exothermic
What effect does catalysts have on equalibrium shifts
They have no effect - they increase forwards and backwards reaction