C7 - Chemical calculations with moles (PAPER 1) Flashcards
what is the yield of a reaction
mass of product obtained from the reaction
what is the theoretical yield of a reaction
the maximum mass of product that could have been produced
why is the actual yield always less than the theoretical yield (3)
- reaction may be reversible
- some product can be lost on separation
- unexpected side reactions between reactants
how is percentage yield calculated
actual yield / theoretical yield x 100
what is the percentage yield
actual yield as a proportion of theoretical yield
what is atom economy
a measure of how many atoms of the reactants end up as useful products
why is a high atom economy desirable
results in less waste and can be more sustainable
how is percentage atom economy calculated
Mr of useful products / Mr of all products x 100
how can concentration in mol/dm^3 be calculated
moles of solute / volume (dm^3)
what is a titraion
method used to calculate the concentration of an unknown solution
What is the end-point (titration)
the point at which the reaction is complete and no substance is in excess (when the indicator changes colour)
How should solution be added from the burette close to the end point
drop by drop, swirling in between
why is a white tile used in a titration
to see the colour change better
what is a titre
volume of solution added from the burette
what are concordant titres
titres within 0.1 cm^3 of each other
