science rev

• Mole


  The amount of matter with the same number of particles (atoms, molecules, ions, or formula units) as the number of atoms present in exactly 12 grams of the isotope carbon-12. Abbreviated as mol and symbolized as n.
• Avogadro's number


  6.022 x 10^23 particles per mole
• Particles in a mole

  • Atoms
  • Ions
  • Formula units
  • Molecules
• Determining the number of particles

  • 1 mole of Cl- = 6.033 x 10^23 chloride ions
  • 2 moles of Mo = 2 x 6.022 x 10^23 Molybdenum atoms
• Atomic mass unit (amu)


  The mass equivalent to 1/12 of the carbon-12 isotope
• Atomic mass


  The average of the masses of naturally occurring isotopes, taking into account their relative abundance
• Calculating atomic mass


  AMi x RAi
• The mass (in grams) of one mole of an element has an equal numerical value as that of atomic mass (in amu) of the element
• Molar mass (M)


  The mass per one mole of a given elementary entity, with units of g/mol or kg/mol
• Calculating molar mass


  Mi x ni
• Molar mass has an equal numerical value with the atomic mass if the substance is an element
• Molecular mass


  The molar mass of covalent compounds
• Formula mass


  The molar mass of an ionic compound
• Calculating average atomic mass

  • Atomic Massaverage Mg = (23.9850)(78.99/100) + (24.9858)(10.00/100) + (25.9826)(11.01/100) = 24.31 amu

  
• Calculating molar mass of phosphate rock


  • Ca: 3 x 40 = 120
  • P: 1 x 2 x 31 = 62
  • O: 4 x 2 x 16 = 128
  • Total = 310 g/mol