I really enjoyed this lab. After reading the introduction I started by making my own flow sheet of how I thought this lab would work. I was reminded about solubility which is defined as the amount of the solute that will dissolve in a given amount of solvent and that the extent to which a substance dissolves depends mainly upon the physical properties of the solvent and of the solute and to some extent upon the solvent’s temperature.
With that being said I came to the conclusions that the salt would need hot water to separate from the mixture, the benzoic acid would need cold water to separate, the sand would settle on its own, and the iron filings could be separated with a magnet. My flow sheet was pretty accurate. We started by separating the iron, which was by far the coolest part, watching the magnet pull up every tiny filing of iron out of the mixture was awesome.
Getting that iron onto the scale and off of the magnet was the hard part though. I removed the plastic, which I had wrapped around the magnet, but when I removed the plastic the iron filings simply left the plastic and continued to cling to the magnet, so I had to scrape them off and onto the scale by hand. Separating the sand was also pretty straightforward, we boiled the mixture in water in the beaker and the sand settled on its own. We poured out the solution into a paper cup, leaving the sand in the beaker. We attempted to heat the sand slowly to dry it out, but there was one big splatter that occurred and we lost a tiny bit of sand, but we then scrapped the sand out of the beaker and onto the scale to weigh it as best we could.
Then adding the paper cup solution to a cup of ice water we watched as the benzoic acid crystalized and floated to the top. We then poured that solution through a filter and funnel into another cup, only allowing the saltwater solution to pass through the filter. The filter was left with a small, shiny, silver substance stuck to it which we laid out on a paper towel and let dry, if that is really a food preservative I am officially grossed out. Benzoic acid looked cool, but nothing I would want to eat. The salt solution was now in a paper cup at 4:30pm 9/18.
Both substances were left overnight to dry out and by noon 9/19 both substances were dry. After weighing each solid and adding the total together we noticed our final total was 5.1g and our initial weight of the mixture was 7.2g. I believe in the transferring process some of each of the solid was lost, being stuck to the beaker, spilled on the floor or counter top or stuck to the paper towel and therefore being unaccounted for. This lab was very interesting though in showing me the different ways to separate each substance.