Answer to Question #224412 in Physical Chemistry for Mojo

Question

An iron wire weighs 2.225g. It’s dissolved in an acid which oxidizes to Fe²⁺ and made up of 250cm^3. A 25cm³ of sample required is 31cm³ of a 0.0185mol L^-1 solution of potassium dichromate in a titration.

1. Calculate the number of moles of potassium dichromate used in the titration?
2. Determine number of moles of iron present in the 250cm³ iron wire solution?
3. Calculate mass of iron present in the iron wire?
4. Calculate percentage of iron present in the iron wire?

Answer 1

Molar Mass of iron = 55.485

Molar Mass of potassium dichromate =294.185

= 18.5 × 31 = 573.5

= 573.5/294.185

= 1.95moles