Hi, On the 2014 paper unit 5 it has this as the last question. Is this old spec knowledge, or are we expected to be able to deduce equations from information like this? I know chromium was emphasised on the old spec. Are we expected to know that Cr2O72- goes to Cr3+? Thanks.
A student carried out an experiment to find the mass of FeSO4.7H2O in an impure
The student recorded the mass of X. This sample was dissolved in water and made
up to 250 cm3 of solution.
The student found that, after an excess of acid had been added, 25.0 cm3 of this
solution reacted with 21.3 cm3 of a 0.0150 mol dm–3 solution of K2Cr2O7
8 (a) Use this information to calculate a value for the mass of FeSO4.7H2O in the sample