e4.4

Experiment 4.5 Redox Tiration N92Q1 : 

Experiment 4.5 Redox Tiration N92Q1 Pipette a 25.0 cm3 (or 20.0 cm3) portion of P into a flask and titrate with Q. At first, the purple colour disappears rapidly but, as the titration proceeds, this disappearance is less rapid until at the end-point one drop of Q produces a pink colour that does not disappear on swirling. Record your results in the table, repeating the titration as many times as you consider necessary to achieve consistent results. within 0.10 cm3 1dp

Burette Readings : 

Burette Readings 20.0 cm3 of P required 19.40 cm3 of Q for complete reaction. Iron (II) sulfate solution turned from pale green to pink at end point. 2dp

My Summary : 

My Summary

Slide 4: 

Q is 0.0200 mol/dm3 potassium manganate(VII). 5 moles of iron(II) sulfate react with 1 mole of potassium manganate(VII). Using the titration results, calculate the concentration, in mol/dm3, of FeSO4.xH2O present in P. No. of mol of KMnO4 used = No. of mol of FeSO4 present = Conc of FeSO4.xH2O =

Slide 5: 

(d) P contains 27.0 g/dm3 FeSO4.xH2O. Using your answer to (c), calculate the relative molecular mass of FeSO4.xH2O. Conc of FeSO4.xH2O = 0.0970 mol/dm3 = 27.0 g/dm3 Mass of 0.0970 mol of FeSO4.xH2O = 27.0g Mass of 1 mol of FeSO4.xH2O = 27  0.0970 = 278.3 = 278 g Mr(FeSO4.xH2O) = 278

Slide 6: 

(e) The relative molecular masses, Mr of FeSO4 and H2O are 152 and 18, respectively. Using your answer to (d), calculate the value of x in the formula FeSO4.xH2O. Mr (FeSO4. xH2O) = 278 152 + x(18) =278 x = = 7 (correct to whole number)