Before beginning, set up a data table similar to the Data Table: Experiment Results in the Lab
Report Assistant section.
This experiment will create a reaction of sodium carbonate and calcium chloride dihydrate to produce a precipitate of calcium carbonate. This formula is:
Na2CO3(aq) + CaCl2. 2H2O(aq) à CaCO3(s) + 2NaCl(aq) + 2H2O
1. Put on your goggles.
2. Weigh out 1.0 g of CaCl2·2H2O and put it into the 100-mL beaker. Add 25 mL of distilled water and stir to form the calcium chloride solution. Use only distilled water since tap water may have impurities that interfere with the experiment.
3. Use stoichiometry to determine how much Na2CO3 you will need for a full reaction.
4. Weigh the calculated amount of Na2CO3 and put it in a small paper cup. Add 25 mL of distilled water and stir to make a sodium carbonate solution.
5. Pour the sodium carbonate solution from the paper cup into the beaker with the calcium chloride solution. A precipitate of calcium carbonate will form instantly.
6. Use the following instructions to set up a filtration assembly.
●● Set a small paper cup inside a slightly larger coffee cup or similar to give the paper cup support and prevent it from tipping over when you add a funnel.
●● Fold a sheet of filter paper in half and then in half again as illustrated. Weigh it.
●● Open one section of the folded filter paper as shown in the bottom illustration.
●● Place the opened filter paper into the funnel and the funnel into the paper cup supported by the coffee cup. www.LabPaq.com 116 ©Hands-On Labs, Inc.
Experiment Stoichiometry of a Precipitation Reaction
7. Swirl the contents of the beaker to dislodge any precipitate from the sides. Then, while holding the filter paper in place and open, slowly pour the content of the beaker into the filter paperlined funnel. Be careful to not let the solution overflow the level of the filter paper while pouring. 8. Measure out 2 to 5 mL of distilled water into