M3: Mole Concept

• DEFINITION OF MOLE

  ● the amount of a substance that contains the same number of entities as there are atoms in exactly 12 g of carbon-12
• AVOGADRO'S NUMBER

  1 mol = 6.022 x 10^23 entities

  The term 'entities' refers to atoms, ions, molecules, formula units, or electrons – in fact, any type of particle. Usually:

  If compounds, molecules.

  If molecular elements, atoms or ions

  ● Abbreviated as NA

  ● Named after Amadeo Avogadro, a French Scientist who introduced Avogadro’s Law

  ○ “equal volumes of all gasses, at the same temperature and pressure, have the same number of molecules”

  ● Value was first estimated by Josef Loschmidt
• MOLAR MASS

  It is the mass per mole of entities (atoms, molecules or

  formula units) of a substance

  ● Unit: g/mol

  • g/mol = amu
• amu = atomic mass

  g/mol = molas mass
• EMPIRICAL FORMULA

  ● The simplest formula for a compound that agrees with the elemental analysis

  ● shows the lowest whole number of moles and gives the relative number of atoms
• MOLECULAR FORMULA

  ● shows the actual number of atoms of each element in a molecule of the compound.