amounts of substance Flashcards
what is the mole
mass of a substance that has the same number of “particles” as there are atoms in 12g of carbon 12
symbol of mole
mol
what could the “particles” be
atoms, molecules, ions or electrons
what is the Avogadro’s constant
the number of particles in one mole
6.02 x 10^23
number of particles =
number of moles x N(A)
what is the mass of 1 mole usually measured in
grams
what is the mass of 1 mole referred to
as the molar mass
do Mr and Ar have units
no
Mr is also the same as
molar mass
units of molar mass
g/mol
how to work out moles
moles = mass/mr
what is in 1 mole
there are the same number of formula units a consant called Avogadros constant
how would we calculate the amount of atoms
1) calculate the number of moles
2) multiply the moles by Avogadros constant
how many atoms in 78g of H2
78/2 = 39 moles
39 x 6.02 x 10^23 = 2.35 x 10^25
