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What is the yield of a reaction?
mass of product obtained from the reaction
What is the theoretical yield of a reaction?
maximum mass of the product that could have been produced
Why is actual yield always less than theoretical yield?
-reaction may be reversible
-some of the product can be lost on seperation
-unexpected side reactoin between reatants
What is the percentage yield?
actual yield as a proportion of theoretical yield
How is the percentage yield calculated?
actual yield x 100
theoretical yield
What is atom economy?
a measure of how many of the atoms in the reactants end up as useful product
Why is high atom econmony desirable?
results in less waste/is more sustainable
How is percentage atom economy calculated?
Mr of useful product x100
Mr of all products
How can concentration in mol/dm3 be calculated?
moles of solute
volume (dm3)
What is titration?
method used to calculate the concentration of an unknown solution
What is the end-point?
the point at which the reaction is complete (when the in dicator changes colour) and no substance is in excess
name of universal indicator used in titration
phenopthalien
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 titration?
to see the colour changge better
What is the titre?
the volume of solution added from the burette
What are concordant titres?
titres within 0.1cm³ of each other
What volume does on mole of any gas occupy at room temperature and pressure?
24dm3 or 24000cm3
What is the conversation of mass?
in a chemical reaction, atoms are not created or destroyed, just rearranged, so total mass before = total mass after the reaction
When a metal forms a metal oxide, why does the mass increase?
atoms from gaseous oxygen have been added
When an acid reacts with a metal, why does the mass decrease?
a gas is produced and escapes
What is the realtive formula mass?
the sum of the relative atomic masses of each atom in a substance
What is a mole?
mass of a substance that contains 6.02x10^23 particles
Which formula is used to calculate the number of moles from maas and Mr
mass = mr mole
