Quantitate Analysis Flashcards
when doing a titrations calculation what 3 things should u keep in mind
- work out the number of moles
- use equation to work out moles of unknown solution
- use mole and volume to work out concentration
what do titration reactions show
how much acid is required to neutralise alkali and produce salts
what are the steps for a titration reaction
- using a pipette and a set volume of alkali into a flask and a few drops of indicator
- fill burette with acid and slowly add acid in at a time swirling the flask
- once change colour alkali is neutralised
record volume of acid needed to neutralise the alkali - repeat till u get similar results
why cant you use universal indicator
because it changes colour gradually
why should you use a white tile
because make colour change easier to see
what colour does phenolphthalein change in alkali and acid
pink in alkali and colourless in acid
what colour does methyl orange change in alkali and acid
yellow in alkali and red in acid
why don’t you ever get 100% yield
- incomplete reactions- no all are converted maybe due to reversible reaction
- practical loss - loss during transfer
- unwanted reactions - impurities in reactants
what does high percentage yield allow
low waste and cost
what is the equation of percentage yield
actual yield/theoretical yield times by 100
What is atom economy
percentage of the mass of reactants become useful products
what is the equation for atom economy
desired mr/total mr times by 100
what does it mean if atom economy is low
not so sustainable
what do low atom economy reactions have
Reactions that have low atom economies use up a lot of resources and produce a lot of waste material which then needs to be disposed of, a very expensive procedure
what is a disadvantage of low atom economy
They are not economically attractive as raw materials tend to be expensive, as does waste disposal which requires chemicals, equipment, space and transport
