Lab#3 Separation of a Mixture of Solids
1. Separating out the Iron – this method uses irons property of being magnetic to single it out from the other substances which do not respond to a magnet. a) Use scale to find the mass of your weighing boat. Then pour the mixture of solids into the boat and weigh it again.
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Then find the net mass of the mixture by taking the weight of the weighing boat and mixture and subtracting the mass of just the weighing boat. b) Spread mixture into a thin layer on a sheet of paper. Cut the second piece of paper into a 10-cm square, weigh and record its mass. c) Cut the plastic into a small square t fit around the magnet.
Wrap plastic over the magnet. Then pass magnet closely over the surface of the mixture. Repeat several times, and then hold magnet over the square of paper, carefully remove plastic to let iron fall to the paper. Weigh it and determine the net mass of the iron fillings. 2. Separating out the Sand – this method involves dissolving all soluble remaining substances so the only thing left is sand since it does not dissolve into water. a) Put the remaining mixture into the beaker and 50mL of water.
Set up beaker stand and fuel, and heat beaker to near boiling. Stir the mixture until all the soluble materials have dissolved. Then pour the liquid into a paper cup, the sand should be left in the beaker. b) Put about 15mL of water into the beaker, heat, and pour out again to make sure all the remaining salt and benzoic acid is removed. c) Make an ice bath, and put your paper cup containing benzoic acid and salt solution into it. Set aside.
d) Dump sand onto paper towels and let air dry. After sand is completely dry, transfer to weighing boat and determine the net mass of the sand. 3. Separating out the Benzoic Acid – this method uses filtration, because the benzoic acid crystals will not pass through, but the water and salt solution will. a) Weigh a paper cup and record weight. Fold the filter paper in half and then in half again and weigh it. Put filter paper into funnel.
Then remove the cup containing salt and benzoic acid crystals from ice bath. Swirl it a little to dislodge any crystals that get stuck on the sides, and pour contents into the filter lined funnel. After it has fully drained through, pour about 5mL more to clean the edges of filter. b) Take out the filter, and place it onto a paper towel and let air-dry. When completely dry, weigh it and calculate the net weight of the benzoic acid crystals.
4. Separating out the Salt – this process uses evaporation to remove the water from the salt so it can be in its pure form. a) Set paper cup from above with the salt and water solution in a place it will not be disturbed. When it is completely dry and all the water had been evaporated, weigh the cup with the crystals and determine the net weight of the salt. 5. Clean, rinse, and pack away all equipment. Throw away used cups and paper towels, and dispose of the substances.