We had to do a very simple diffusion experiment in anatomy and physiology involving a suspension with Copper sulfate + charcoal + starch + water in one big breaker. We setup an Erlenmeyer flask with a funnel cone and placed a filter paper inside the funnel cone.We then re-mixed the copper sulfate etc.. suspension to resuspend the particles and poured through the funnel cone.The charcoal never penetrated the filter paper nor did the starch due to their size. But I forget if the copper sulfate penetrated or not. I know it was blue. So technically, if our filtrate was blue, then it penetrated. but I forgot.Does anyone know if the copper sulfate molecule penetrates the filter paper when doing filtration experiments? or is it simply too big? Thanks you.
Copper (II) sulfate is pretty well soluble in water, so you don't have any macroscopic aggregates of the salt in your mixture; as it is dissolved, the copper and sulfate ions (talking about molecules with salts is a little touchy) can pass the filter unhindered - you'd need to use molecular sieves with pores in the range of Angstroms to filter out these very small ions.That the water used as a solvent remains blue after filtration is an indication that the copper sulfate passed through, as blue is a typical color for copper (II) ions in solution. You could also test for the presence of copper sulfate in the filtrate by simply letting the water evaporate; if you do that slowly enough, you can get back nice blue crystals.
3 The filter paper will not allow relatively large particles to pass through it. However, water molecules and the copper and sulfate ions are very small --- molecular size --- and can easily pass through. Any undissolved copper sulfate would remain behind on the filter paper.
