TITLE: Egg Shell Lab
OBJECTIVE: To determine and compare the amount of calcium carbonate content of brown and white eggshells. MATERIALS: white and brown eggshells, water, deionized water, beaker, pipet, flask, test tube brush, funnel, hotplate, mortar, pestle, ethanol, HCl, phenolphthalein indicator, sodium hydroxide PROCEDURE:
(Complete for both white and brown eggshells)
1.Get one egg and beaker and bring it to your lab station.
2.Break the egg into a beaker.
3.Add water to the egg and stir before you pour it down the drain. 4.Wash the shell with deionized water and peel off the membranes from the inside of the shell. Dry your eggshell and put into a labeled beaker. 5.Wash your hands.
6.Dry the shell for about 10 minutes in the oven.
7.Grind the shell to a fine powder with a mortar and pestle. 8.Weigh between 0.450 and 0.550 grams of dried shell into each of the 3 labeled 250mL flasks. 9. Make sure to record the exact mass of the shell in each flask. 10. Add a few drops of ethanol to each flask.
11. Pour 40 mL of 1.0M HCl into a beaker.
12.Put 10.0 mL of the 1.0M HCl to each 250mL flask containing the eggshells. Whirl the flasks to make sure all of the solids get wet. Be sure to spill any extra HCl into the sink with water. 13.On a hotplate, heat the solutions in the 250 mL flasks until they boil and then wait for them to cool. Be careful not to let them boil dry. Rinse flask with water. 14.Carefully, add 3-4 drops of phenolphthalein indicator to each flask. 15.Using a funnel, fill a buret partly with 0.100 M sodium hydroxide, to rinse it. Empty the buret into the sink. Then, pour NaOH solution into the buret just above the top mark. Spill out some excess solution to remove all of the bubbles from the top. If there is not enough solution, refill some more into the buret. Read and record the initial volume to ± 0.01 mL. 16.Add one sample to the first pink color. The color will fade...