Topic 4 - reversible reactions and equilibria

what are chemical reactions

reversible

what is used for the reversible reaction

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the direction of some reversible reactions can be altered by changing the reaction conditions

what are the conditions for the Haber process

• temperature at 450C

• Pressure 200 atmospheres

• iron catalyst

Describe the formation of ammonia as a reversible reaction

between nitrogen (extracted from the air) and hydrogen

(obtained from natural gas) and that it can reach a dynamic

equilibrium

what happens to the dynamic equilibrium when you increase the temp

• POE moves to the endo side

• Yield increases

• Rate increases as the particles gain energy which makes them move faster therefore creating more effective collisions per second

• does the opposite when u decrease the temp

How does the POE change when it is affected by a catalyst

• POE is not affected, the equilibrium is just achieved faster

• Yield is not affected

• Rate of reaction increases as the catalyst provides a pathway via a lower activation energy

How does the POE change when it is affected by the change in pressure

• The equilibrium moves to the side with fewer moles - always count the amount of moles

• This allows you to see if pressure inc or dec

• if n.o moles are the same the POE will be the same

• Yield increases

• INcrease in pressure as the particles are closer together

How does the POE change when it is affected by a change in concentration

depends on what you are changing

• if you increase the concentration then there are more particles,same volume. so therefore more effective collisions per second

• Yield of … increase / decrease