Task

In the lab, 400 g of an 8 % copper(II) sulfate solution (density 1.084 g/mL) was prepared from blue vitriol (CuSO₄·5H₂O) and water. The solution was then electrolysed with inert electrodes at 5 A, and electrolysis was stopped when the mass of the solution had decreased by 12 g. 1) Calculate the masses of blue vitriol and water needed to prepare the solution. 2) Find the molar concentration (mol/L) of the initial solution. 3) Write the overall electrolysis equation and calculate the mass fractions (%) of the solutes after electrolysis. 4) Determine how long (min) the electrolysis lasted (F = 96500 C/mol, 100 % current efficiency). For every part, show the method (reaction equations, formulas, reasoning) and all calculations step by step.