Record the initial buret reading and dispense as close as you can to the required volume of CaCl 2 into a clean Erlenmeyer flask. While it would be nice to get as close as possible to the recommended volume, it doesn't have to be exact, so long as you record the final buret reading. Use the same procedure as 2 above to dispense as close as possible to the recommended amount of Na 2 CO 3 into the Erlenmeyer that contains the CaCl 2 . Initially you may not observe a precipitate. Swirl the flask and one should quickly form.
Gravity filter the white solid.
This is done by folding a piece of filter paper into quarters and making a funnel. Place this inside your glass funnel. Pour the solution into the center of the filter paper taking care not to let it get above the level of the filter paper. This is a good time to start the procedure over for the next reaction. When the paper is dry remove the watch glass from the water bath.