# Amount of Substance - Chapter 2

• Created by: 12BurtD
• Created on: 16-03-18 18:33
• Amount of Substance
• Relative Atomic Mass
• Ar
• The average mass of an atom of an element (including isotopes) relative to 1/12 the Ar of Carbon-12
• Relative Molecular Mass
• Mr
• The mass of a molecule compared to 1/12 the Ar of Carbon-12
• Relative Formula Mass
• Used for ions since they don't exist as Molecules
• The number of atoms in 12g of Carbon-12
• The Mole
• The amount of a substance that contains Avogadro number of particles
• Equations
• n = m / Mr
• m - g         n - mol
• n = cV
• n = cV / 1000
• c - mol dm^-3     V - cm^3
• c - mol dm^-3    V - dm^3
• PV = nRT
• P - Pa             V - m^3           n - mol            R - 8.31     T - K
• Gas Laws
• Boyle's
• PV = constant
• Charles'
• V/T = constant
• Gay-Lussac's
• P/T = constant
• 6.022x10^23
• Formulae
• Empiricle
• 1) Mass/%-age
• 2) Relative Mass
• 3) Moles
• 4) Divide by smallest
• 5) Make simplest ratio
• Molecular
• Ar of Molecule / RM of empirical formula of molecule
• Atom Economy
• (mass of desired products / total mass of reactants) x 100
• Percentage Yield
• (number of moles of specified product / theoretical max. moles of product) x 100
• Ar
• The average mass of an atom of an element (including isotopes) relative to 1/12 the Ar of Carbon-12