(c) density computation exercise [15 marks] hematite and magnetite are two main fe-oxides, and are composed of fe and o. hematite has hexagonal close packing (hcp) and magnetite has "cubic diamond type" packing, i. e. combining cubic close packed (ccp) and face centred cubic (fcc). (see example used in class). hematite crystallises in the hexagonal system with cell parameters: a b 5.038 a c 13.772a, and angles a b 90°; and y 1200. magnetite is cubic with a b -c 8.397 a, a b y 90 given the atomic masses of fe and o as 55.845 g/mol, and 15.999 g/mol, respectively, calculate the density of hematite and magnetite hints: use the following relationships for your density calculations if mat is the atomic mass in the periodic table (given above for each element) then the mass of the atom (ma) in kg is: (1) mat (103 kg/g)ma/na where na is avogadro's number na=6.023x1023 atom/mol and density is: (2) p (number of atoms per unit volume) x (mass per atom)