Chemistry 100 Experiment 3 Addendum

For this experiment, you will separate NaCl, Iron and CaCO₃ from a mixture.  Using the amount of recovered material you will determine a percent composition of the mixture.  Also, based on the amount of material you collect, you will determine a percent yield of total product.

To do the experiment, you could follow the procedure outlined below.

• Weigh out about 5 grams of mixture (you don't need exactly 5.000 g, but you can use a mass of between 4.5 and 5.5 g).  Just be certain you know the mass of your mixture to three decimal places.
• Use a magnet to remove the iron filings.  Mass the recovered iron.
• Add 15 mL of water to the remaining mixture to dissolve the NaCl.
• Filter the water-NaCl-CaCO₃ mixture to collect the filtrate containing NaCl.  Use a pre-weighed sample of filter paper and place the filter paper, with CaCO₃ pieces.
• Using an evaporating dish, evaporate the water to reclaim the NaCl.  If all the water is not evaporated, place the evaporating dish in the oven to continue to dry until the next lab period.
• Weigh the dry evaporating dish, with NaCl, to determine the mass of recovered NaCl.
• Weigh the dry filter paper with CaCO₃ to determine the mass of CaCO₃ recovered.

Add the masses of the Fe, CaCO₃ and NaCl to get a total mass of recovered material.  Use this total mass to determine the percent composition for each component.

Use the total mass determine above to determine a percent yield compared to the mass of your starting mixture.