How do I do redox calculations?
For example,Iron(II) sulphate can be oxidised using acidified potassium permanganate solution. Calculate the mass of iron(II) sulphate which will completely react with 200 cm3 of 0.25 mol l-1 acidified permanganate solution.
Write the redox equation:-2MnO4- + 16H+ + 5Fe2+ à 2Mn2+ + 8H2O + 5Fe3+
Calculate the number of moles of the ‘known’ reactantNo. of moles = C x V(litres)= 0.25 x 0.2 = 0.05 mol
Use: mole ratio in equation to calculate the number of moles ofthe ‘unkown’ reactant.0.05 mol of MnO4- reacts with 5/2 x 0.05 = 0.125 mol of Fe2+
Use: mass = no. of mole x gfm to calculate the mass of iron(II) sulphate Mass of FeSO4 = number of moles x gfmMass of Fe SO4 = 0.125 x152 = 19g
CG
Related Chemistry A Level answers
All answers ▸Why does ice float on water?
Describe how you could distinguish between ethanol, ethanoic acid, ethyl bromide and 2-methylpropan-1-ol.
The Haber process is used to produce ammonia. (Insert equation here) Explain the optimum conditions for this reaction and why these may differ from the conditions used in industry.
The bond angle in a molecule of ammonia (NH3) is 107 degrees so why, when part of a transition metal complex is the bond angle 109.5 degrees.