Things I forget

• used to find the number of moles of a substance by reacting it with an excess volume of reactant of known concentration • the resulting mixture is then titrated to work out the number of moles of the reactant in excess • from the initial number of moles of that reactant, the number of moles used in the reaction can be determined • the initial number of moles of the substance being analysed can then be calculated

when trying to work out the quantity of a substance in a solid with low solubility

• available in a high state of purity • be stable when solid and in solution • be soluble • have a reasonable high GFM

sodium carbonate hydrated oxalic acid potassium hydrogen phthalate silver nitrate potassium iodate potassium dichromate

• has a relatively low GFM • is unstable as a solid (absorbs moisture) and unstable as a solution

• mass transfer or mechanical losses • purification of product • side reactions • equilibrium position

1mg per kg or 1mg per liter

• Em radiation is detected at an atomised sample • radiation is absorbed as electrons are promoted to higher energy levels

by measuring how the intensity of light varies with wavelength

• high temperatures are used to excited electrons within atoms • as the electrons drop to lower energy levels, photons are emitted

by measuring the intensity of light emitted at different wavelengths.

the magnetic quantum number (ml) determines the orientation of the orbital and can have values between -l and +l

electrons fill orbitals in order of increasing energy

when degenerate orbitals are available, electrons fill each singly, keeping their spins parallel before spin pairing starts

linear 180

trigonal planar 120

tetrahedral 109.5

trigonal bipyramidal 90, 120, 180

octahedral 90

non bonding pair/non bonding pair>non bonding/bonding>bonding/bonding

C2O4 2-

CN -

• in terms of d-d transitions • light is absorbed when electron in a lower energy d orbital are promoted to a d orbital of higher energy • if light of one colour is absorbed, then the complementary colour will be observed

• in terms of the formation of activiated complexes and absorption of reactive molecules onto active sites • the presence of unpaired d electrons or unfilled d orbitals is thought to allow activated complexes to form • this can provide reaction pathways with lower activation energies compared to the uncatalysed reaction