3.1.2 amount of substance Flashcards
define relative atomic mass
the average mass of an atom x12 / mass of an atom of carbon-12
define relative molecular mass
the average mass of a molecule x12 / the mass of an atom of carbon-12
define mole
unit for the amount of substance that contains as many particles as there are in 12g of carbon-12
how do you calculate number of particles
N= n x L
N= no. of particles
n = no. of moles
L = avogadros constant
what is the equation for concentration in mol dm-3
concentration = moles / volume
what is the equation for concentration in g/dm3
concentration = mass / volume
how do you convert between mol dm3 to g dm3?
mol dm3 — g dm3 ( multiply by Mr)
what is the ideal gas equation?
PV = nRT
p = pressure ( pascals )
v = volume (m3)
n = no. of moles
r = gas constant
t = temperature ( kelvin)
define empirical formula
the simplest whole number ratio of atoms of each element in a compound
define molecular formula
the number of atoms of each element in a molecule
what is percentage yield?
an indicator of how successful the reaction and process has been at producing the desired product
what is theoretical yield?
maximum mass of product expected from the reaction, calculated using reacting masses
what is actual yield?
mass of the product that is actually obtained from the real chemical reaction
what is the equation for % yield?
% yield = actual yield/ theoretical yield x 100
what is atom economy?
a measure of the proportion of reactant atoms that form the desired product of the reaction
