1. Separating out the Iron
a. Use your digital scale to determine the mass of your weighing dish.
b. Empty the entire mixture of solids from the plastic bag into the weighing dish and determine the gross mass of the total mixture and weighing dish. Compute the net mass of the mixture: this is equal to the gross mass of the weighing dish with the mixture less the mass of just the weighing dish determined in 1-A.
c. Spread the mixture into a very thin layer over a full sized piece of paper.
d. Cut a second piece of paper into a 10-cm square. Weigh and record its mass and set it aside.
e. Wrap a small square of clear plastic over the magnet. Remove the iron powder/filings by passing the magnet closely over the surface of the entire mixture. Repeat several times to make sure you’ve collected all the iron.
f. Holding the magnet over the 10-cm square of paper, carefully remove the plastic and allow all the iron to fall onto the paper. Weigh and determine the net mass of the iron powder/filings.
2. Separating out the Sand
a. Put the remaining mixture, containing sand, benzoic acid, and table salt into your beaker and add 50 mL of distilled water.
b. Set up the beaker stand and burner fuel and heat the beaker of solids and water to near boiling. Stir the mixture to make sure all soluble material dissolves. At this point, the benzoic acid and the sodium chloride should have dissolved and been extracted from the insoluble sand.
c. Decant (pour) the liquid while it is hot into a small paper or Styrofoam® cup.
d. Pour another 10 to 15 mL of distilled water into the beaker containing the sand, bring the mixture to a boil, and decant again into the same cup used in 2-C. This assures that any remaining salt and benzoic acid is removed from the sand.
e. Make an ice bath by