Separation of a Mixture of Solids

Purpose: This experiment allowed me to learn different separation techniques for various substances based on their specific chemical properties. Procedure: I began this experiment by using a magnet to pick up and collect the iron filings out of the mixture. Then the sand was separated by placing the mixture into a beaker and boiling it in distilled water in order to dissolve the salt and benzoic acid, once boiling the liquid was poured out leaving the sand behind; which was then heated until dry. The next step was to use filter paper to separate the benzoic acid from the salt. Once the liquid was poured through the filter paper it was set aside to allow the benzoic acid to cool. The final step was separating the salt, which was done by allowing the cup containing the filtered solution to set out until the excess water had evaporated and only the salt was remaining.

Questions:
A. I was pretty certain the magnet would be used to collect the iron filings. I also thought that some type of filtration would be used to separate the sand, and honestly didn’t have a clue as to how to separate the benzoic acid. I did presume that distillation would be used to separate the salt. The actual method of boiling and dissolving the salt and benzoic acid was very interesting; and I did not expect the sand to simply stay put when pouring out the other elements.

B. I would expect there to be a large margin of human error, especially when dissolving the salt and benzoic acid.

C. If the benzoic acid wasn’t fully dissolved and separated a portion of it could have been measured in with the sand particles.

D. There are several potential sources of error; if you didn’t get all of the benzoic acid out of the sand your values would be different. If your salt was not completely dissolved it wouldn’t have all filtered through benzoic acid crystals giving that a different weight. Even not allowing the sand and benzoic acid to cool completely would have given you inaccurate results. Conclusions: I found this experiment very intriguing, I learned several new ways of separating a mixture of solids and was able to use those methods to better understand each elements chemical properties.