Question

calculate the mass of potassium dichromate required to prepare 100 cm^3 of a 2.00*10^-3 mol*dm^-3 solution....................................please show calculations

Answer 1

please help out guys

Answer 2

First, write down the chemical equation for potassium dichromate and work out its molar mass.

Answer 3

Molarity = 2*10^-3 M = 2*10^-3 moles/liter.
Molar mass of K2Cr2O7= 294.2 grams/mole.
No. of moles of K2Cr2O7 in 100 ml of solution = 0.1*2*10^-3 = 2*10^-4 moles.
=> mass of K2Cr2O7 required is ( 2*10^-4 ) *294.2 = 0.0588 grams.