Unit 1.2

• Number of particles = Number of moles x Avogadro's constant
• Relative isotopic mass - Mass of an atom of an isotope compared with 1/12th the mass of carbon-12
• Relative atomic mass - the weighted mean mass of an atom of an element compared with 1/12th the mass of carbon-12
• Relative atomic mass = (Relative isotopic mass of isotope 1 x Percent abundance of isotope 1) + (Relative isotopic mass of isotope 2 x Percent abundance of isotope 2)/100
• Relative formula mass is used for giant structures
• Molar mass = Mass of 1 mole
• Amount of substance = Mass/Molar mass
• Number of atoms = number of particles x Avagadros constant
• Units of volume

  
• Concentration (C) moldm^-3 = number of mole (n)/ Volume (V) dm^3 -> xMr= mass(g)/volume
• Assumptions for ideal gas:

  • Particles are points in random motion
  • Particles don't interact
  • This is not true as particles do affect each others but calculation is too difficult
• pV = nRT
• p = Pressure (Pa)
• V = Volume (m^3)
• n = number of moles
• T = Temperature (K)
• R = Gas Constant (8.31Jk^1mole^-1)
• Empirical formula - The smallest whole number ratio of the atoms of each element present in a molecule
• Molecular Formula - Gives the actual number of each element in one molecule of the compound
• Percentage yield = Actual yield/Theoretical yield x 100
• Atom economy shows how efficient a reaction is, it shows how much of your starting reactant are wasted and how sustainable the production method is
• Atom economy = Mass of desired product/Total mass of reactants x100