Finishing the Separation

Class on Friday started off as it normally would. Everyone took their seats and the substitute teacher who was filling in for Mr. Lieberman (who is in Florida) told us to start Part B of our separation lab. She also told us to remember to always wear our goggles. Preparation for Part B of the lab required us to make a procedure to separate salt, sand, and iron from a mixture of the three. Our lab group compared our procedures and then got to work on the separation aspect. The first thing we did was find out the mass of the entire mixture which was in a small test tube (4.2 grams). We did this so we could calculate the mass percent of each substance. At first we knew that the only way to extract the iron from the mixture was to use the magnet, so we held the magnet, which was enclosed in a plastic bag, over the mixture and all the iron flew up and stuck to the magnet. After all the iron was stuck to the magnet we put it in a little plastic cup and weighed it in order to find out it's mass (2.36 grams).

After setting the iron filings aside we then added the two remaining substances, salt and sand, to water and began a filtration process.Because the salt dissolved in the water and the sand just sunk to the bottom of the beaker, we knew that the salt and water would pass through and become the filtrate and the sand wouldn't pass through and would be left behind. After all the salt-water passed through, the wet sand was scattered across the piece of paper that was over

the funnel. We took the paper off of the funnel and put it on a hot plate to dry. When the sand was dry we brushed it off the paper and into a plastic cup and weighed it (0.86 grams). You may be able to read the mass in the picture, which says 1.46 grams. This is because it is calculating the mass of the sand and the plastic cup, so to fix this we weighed the cup, which has a mass of 0.6 grams. We then had to subtract this number from every number the scale recorded.

After the sand was removed we were left with the salt-water, and we had two ways of figuring out the mass of the salt. We knew that if we boiled the water, it would evaporate and the salt would be left in the beaker. Also, because we knew the mass of all three substances together, and we knew the mass of two individual substances, then by default to find the third we could subtract the mass of two of them from the mass of all of them. We did this calculation and found out that the mass of the salt was 1.08 grams.

After the lab everyone helped clean up the lab stations and then started writing a table for the mass and mass percent of each substance, and then finished up the post-lab questions. Overall I think that the lab taught us that separating substances isn't as hard as it sounds, and can be quite educational as well. The homework for the long weekend is to finish up the Separating Mixtures lab and to answer the pre-lab questions for the What Chemical Reaction Lab.

Finally the next scribe is...... (Ethan S). Thanks for reading my scribe post. Josh out!