Percentage yield and atom economy Flashcards
why do we use relative formula mass to calculate atom economy?
to show how much product should be made in a chemical reaction (predicted yield)
why is the actual yield less?
due to losses in the practical methods used
what is the equation for percentage yield?
percentage yield= actual yield x 100
predicted yield
why do industrial processes need to have as high a percentage yield as possible?
- reduce the amount of reactants wasted, which is wasteful and costly
- reduce their costs by ensuring that enough reactants are used, as too little reduces the amount of product
what is the equation for atom economy?
mass of desired products x 100
sum of mass of all products
balance equation before adding
rem
why do industries want as high atom economy as possible?
- to reduce production of unwanted products that will need to be disposed of
- to make the process more sustainable by making better use of the reactants, so conserving raw materials and avoiding the need to get rid of wasted products
why do we calculate percentage yield?
as a way of comparing the amount of product made (actual yield) to the amount we expect to make (predicted yield)
how can industry get the yield high?
all the reactants need to be converted into the product
how do chemists prevent reactants being wasted?
by calculating the exact amount to use to make a certain amount of product
what does atom economy measure?
the amount of atoms that are wasted or lost when a chemical is made
what does 100% atom economy mean?
all atoms in a reactant have changed into the desired product
how is lime water made?
calcium oxide + water — calcium hydroxide solution (lime water)
what is the equation for atom economy?
relative formula mass of desired product
relative formula mass of all products x 100
what does mr stand for?
relative formula mass
