cal

Question 1

equation for mass.

Answer 1

mass = mr X moles

Question 2

percentage yield

Answer 2

percentage yield = actual yield / theoretical yield.

Question 3

empirical formula

Answer 3

list two elements
write in experimental masses
find moles of elements
find simplest ratio using whole numers

Question 4

you can find empirical formula by combustion

Answer 4

get a crucible and heat so that no traces of liquids and cool and weigh
add some clean magnesium, reweigh crucible an then you need to heat it, slowly add oxygen into the by leaving a small gap in the lid of the crucible. Allow it to cool and then reweigh.

Question 5

how much water of crystallisation a salt can occur. XH20

Answer 5

work out mass of salt and mass of salt and water 
then moles of water lost
moles of anhydrous salt
ratio of water to anhydrous 
then divide water moles by salt mols
X must be a whole number

Question 6

moles concentration volume equation

Answer 6

conc(mol/dm) = mol / dm3

Question 7

volume and moles of gas equation

Answer 7

vol (dm) = moles X 24