the mole and molar mass Flashcards
definition of mole
one mole of any substance contains 6 x 10^23 particles
how is number of moles calculated
mass IN GRAMS divided by molar mass IN GRAMS/MOL
definition of relative molecular mass
the relative molecular mass of a molecular substance is the average mass of one molecule of that element or compound compared to 1/12 of the mass of one carbon-12 atom.
definition of relative atomic mass
the relative atomic mass of an atom is the average mass of one atom of that element compared to 1/12 if the mass of one carbon-12 atom.
why are some atomic masses of some elements not whole numbers?
the relative atomic masses of some elements are not whole numbers . these elements exist as mixtures of isotopes. the Ar is thus calculated based in the relative percentages of the isotopes.
avogadro’s law
one mole of any gas occupies 24dm^3(=24000cm^3) at room temperature and pressure.
this volume is called the molar volume of a gas.
how is number of moles calculated
mass IN GRAMS divided by molar mass IN GRAMS/MOL
how is volume of gas calculated
number of moles multiplied by 24000 cm^3 or 24 dm^3
do balloons of the same volume contain the same number of particles?
yes. according to avogadro’s law the balloons contain the same number of gaseous particles since they have the same volume.
how much volume does one mole of any gas occupy
24dm^3
what type of particle does ammonia exist in
molecules
