mole concept & stoichiometry Flashcards
relative atomic mass def
average mass of an atom of the element, compared to 1/12 the mass of a carbon-12 atom
- indicated on periodic table
relative molecular/formula mass def
average mass of a molecule (ion) of the element or compound compared to 1/12 the mass of a carbon-12 atom
- adding individual Ar of constituent atoms
mole def
one mole = contains 6.02 x 10^23 particles/molecules/atoms/ions/sub-atomic particles of that substance
molar mass def
mass of 1 mole of substance
molar volume def
volume occupied by 1 mole of any gas
- under room temperature and pressure = 24 dm^3
mass of element/molecules in a sample of compound formula
(no of atoms/compound molecules of element in formula x Ar of element/compound)/Mr of sample compound x mass of sample
formula for percentage mass
(no of atoms of the element in formula x Ar of element)/Mr of compound x 100%
formula for number of particles and number of moles
no of particles = no of moles x avogadro’s constant
formula for mass and number of moles
no of moles = mass/molar mass
formula for volume of gases to no of moles
no of moles = volume (of 1 mol of gas)/molar volume (24 dm^3)
- GASES ONLY AT ROOM TEMP AND PRESSURE
formula for concentration of solution and no of moles
conc = no of moles/volume
- only for aqueous solutions ≠ liquid
formula for concentration of solution and mass
conc = mass/volume
formula for concentration and molar mass (to make g/dm^3)
conc (mol/dm^3) x molar mass (g/mol) = conc (g/dm^3)
formula for percentage yield
percentage yield = experimental yield/theoretical yield x 100% (mass/volume)
- experimental yield = often copied from qn
- theoretical yield = calculations
formula for percentage purity
quantity of pure substance (calculated)/quantity of impure substance (qn) x 100%
