Activated charcoal is a form of carbon with a very high surface area. It can be used to remove impurities from mixtures. It does this by a process called adsorption, where particles of the impurity bond (adsorb) to the activated charcoal surface. A student wanted to determine the ability of activated charcoal to adsorb a blue dye (the impurity) from aqueous solution. The equation that links the mass of activated charcoal with the amount of blue dye adsorbed is shown. log (D/m) = A + b log [X] D = difference in concentration of dye (in g dm⁻³) before and after adsorption m = mass of activated charcoal (in g) [X] = final concentration of dye (in g dm⁻³) after adsorption A and b are constants The student used the following procedure to investigate the ability of activated charcoal to adsorb a blue dye from an aqueous solution. • Place a 50.0 cm³ sample of a 25.00 g dm⁻³ solution of blue dye in a conical flask. • Add a weighed mass of activated charcoal to the flask. • Stir the contents of the flask for three minutes and then leave for one hour. • Filter the mixture. • Determine the final concentration of the blue dye, [X], by colorimetry. • Repeat the procedure using different masses of activated charcoal.