Amount Of Substance Flashcards
Molar equation 1 (number of particles , avogadro and moles )
Particles molecules and ions mean same thing
When question asks about ions and atoms what must u do
Make sure to times by the number of atoms/ ions there are
Molar equation 2 - mass mr
Mass over mr = moles
Equation for density (gcm3) with units
Mass(g) / volume (cm3)
Molar equation 3 (volume moles 24 )
Moles = volume dm3 / 24
Molar equation 4 (ideal gas equation) with units
PV= nRT
Molar equation 5 ( concentration volume )with units
n=cv
What does being in excess mean
More than is necessary there’s extra
Whag does limiting reagent mean
Not in excess
How do you know which is excess and which is limiting reagent give example
If u react 0.5 moles with 1 mole u will get 0.5 because only 0.5 can react from the 1 mole
So the 1 mole is in excess as there is 0.5 leftover
0.5 is the limiting reagent because it’s not in excess
What are the steps for reacting masses
Write balanced equation
Work our moles
Using ratio from balanced equation Work out moles of products
Work out mass of product by doing moles x Mr
What must you do when reacting masses with limiting reagents
Work out moles of more than one reactant then use the limiting one in your molar ratio
What equation do you use when your not at RTP
pv=nRT
How do u calculate percentage atom economy
Mr of desired products / mr of all products X 100
What does a high atom economy mean
Less waste produced , high proportion of atoms are in desired products
What does percentage yield tell us
The % molar conversion of reactants to products
How do u calculate % yield
What is theoretical yield also ?
The expected mass calculated during reacting masses
If a substance is impure what can’t you calculate
The moles
How do you calculate percentage purity
Actual mass/ impure mass X 100
