Chemistry Paper 5 EdexcelWatch
(b) In such an experiment 22.50 CM3 of 0.0200 mol dm-3 aqueous potassium manganate(VII) KMnO4 was required to oxidise 25.0cm3 of aqueous IRON(II) Sulphate, FeSo4.
(i) Write half equations for
The oxidation of the iron(II) ion, Fe2+
the reduction of the manganate(VII)ion, MnO4- in acidic solution.
(III) Calculate the concentration of the IRON(II) Sulphate solution.
(5a)Name the type of reaction occuring with [Cr(H2O)6]3+ with EXCESS NH3.
(5e) state with reasons the number of peaks in the NMR spectra of propanone and propanal.
In response to your questions:
1) Pipette a known volume of iron (II) sulphate solution into a conical flask and add excess dilute sulphuric acid. Fill a burette with a known concentration of potassium manganate (VII) and run in until there is a faint pink colour (minute excess of MnO4- ions).
- I remembered I wrote a bit more than that since it was worth like 5 marks.
b) i) Fe2+ --> Fe3+ + e-
MnO4- + 8H+ +5e- --> Mn2+ + 4H2O
- I got something like 0.09 mol dm^-3 as my final answer for the concentration.
5a) Ligand exchange.
- However, I suspect that the question had an unnoticed erratum since, there should not be any further reaction with excess NH3. This only occurs with excess OH. Anyway.
e) Propanone: 1 peak, only a -CH3 group. Propanal: 3 peaks, 3 groups -CH3, -CH2, and -COH.
u seem to have MAKE THE GRADE NAS CHEMISTRY