posted by Anonymous .
a potassium dichromate is prepared by 0.3525grams of K2Cr2O7 is enough water to yield 250.0mL of solution. a student then measures 10.00mL of an unknown solution of Fe2+ into an erlenmeyer flask and dilutes with 90mL of 1.0M hydrochloric acid. she then titrates this sample with the solution prepared above. if 38.40mL of the potassium dichromate solution is needed to reach the end point, what is the concentration of Fe2+ in the original unknown solution?
mols K2Cr2O7 = grams/molar mass
Then M = mols/L solution.
You can use this information to calculate the concn of the Fe^2+ in the 10.00 mL sample of unknown ferrous solution BUT you won't now the concn of the original without knowing what the original volume was.