Equilibrium Flashcards
What is the definition of dynamic equilibrium ? (2 marks)
1) concentrations of reactants and products remain constant
2) the rate of the forward = rate of the reverse reaction
Describe how is dynamic equilibrium reached ?
1) start ; forward = fast, backward = slow
2) backward speeds up as forward slows down
3) rate of forward reaction becomes the same as the rate of the backward reaction
State a condition for a reaction in equilibrium ( 1 mark)
Closed system
State Le Chateliers principle
position of equilibrium will shift to oppose the change
A + B <> C + D
concentration of A is increased
1) equilibrium will shift to the right
2) oppose addition of A
3) so yield of C and D increases
A + B <> C + D
concentration of A is decreased
1) equilibrium will shift to the left
2) oppose addition of A
3) so yield of A and B increases
H2 + O2 <> H2O2
why would an industrial manufacturer of hydrogen peroxide increase the amount of hydrogen gas in the mixture ?
1) Equilibrium shifts right
2) To oppose addition of Hydrogen
3) Yield of Product increases
3H2 + N2 <> 2NH3
pressure increased
1) fewer moles on the right
2) equilibrium shifts to the right to oppose the increase in pressure
3) so yield of NH3 increases
3H2 + N2 <> 2NH3
pressure decreased
1) more moles on the left
2) equilibrium shifts to the left to oppose the decrease in pressure
3) so yield of H2 and N2 increases
CH4 + H2O <> CO + 3H2
Use le Chateliers principle to explain why a low pressure should be used to obtain the highest equilibrium yield of H
1) More moles on the right
2) equilibrium shifts right to oppose decrease in pressure
3) yield of H increases
When temp is decreased, equilibrium yield of product increases
3H2 + N2 <> 2NH3
is the forward reaction exo or endo ? explain
1) equilibrium shifts right to oppose decrease in temp
2) yield of NH3 increases
3) forward = exothermic
Why does a catalyst not effect the position of equilibrium
Catalyst increase the rate of forward reaction and backward equally
Why are catalysts added to the harbour process, which is a reversible reaction producing ammonia
to reduce the time taken to reach dynamic equilibrium
Why are compromise conditions necessary ?
- Higher pressure would be too expensive
- 450’C gives a good yield in a fast time
