Percentage yeilds and atom economy Flashcards
How do you calculate the maximum theoretical yeild of a reaction?
calculate the no of moles you started with
What can moles also be refered to as?
Amount of substance
How do you calculate the maximum mass?
Amount in moles x Molar Mass
What do you use to work out maximum theoretical yeild?
Mol ratio
What is the limiting reagent of a reaction?
The reactant that is used up first
What is the theoretcical yeild?
What we can expect assuming every molecule of reactant is used up
What is percentage yeild a measure of?
The efficiency of a reaction
What are some reasons for yeild never being 100%?
Reaction may not have completed
Some product lost when transfering between containers
Unwanted side reactions may occur giving different products
What does the atom economy refer to?
What percentage of the mass of the reactant atoms ends up in the product we want
What is the equation for atom economy?
Molecular mass of desired product
x 100
Sum of molecular masses of all reactants
What is important to keep in mind when calculating atom economy?
It is based purely on the chemical equation for the reaction
It assumes the percentage yeild is 100%
Large numbers in the chemical equation count for atom economy
Any reaction that has one product has an atom economy of 100%
Reactions with a high atom economy are … ?
More sustainable
Reactions with a low atom economy are?
Less sustainable
Why is this?
Less/more of the mass ends up as waste product
What are other factors that need to be considered?
Energy use
If a waste product can be used as a starter for a different reaction
