C5.3.3 - Choosing Reaction Conditions Flashcards
How is methanol made?
Reacting carbon monoxide with hydrogen
What is the equilibrium yield?
The amount of desired product present in a reaction at equilibrium
What factors do the equilibrium yield depend upon?
Pressure, temperature and concentration of reactants
What is Le Chatelier’s principle?
When a change is made to a reaction at equilibrium, the position of equilibrium moves to oppose the change
What are the negatives of using high pressures to obtain high equilibrium yields?
They need a lot of energy to run
They can be hazardous
Why do chemical engineers have to choose a compromise pressure for equilibrium yields?
If the pressure is too low they will not get enough equilibrium yield, and if it is will take a lot of energy and can be hazardous
What are the negatives of using low temperatures to obtain high equilibrium yields?
It can result in a lower equilibrium yield
Slower rate of reaction
Why do chemical engineers have to choose a compromise temperature for equilibrium yields?
If the forward reaction is endothermic, the temperature needs to be low so the equilibrium yield will be high, but the rate of reaction will be low
