Eggshell Lab Report

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Eggshell Titration Lab Report LIU-1 Mr. Silva Beko Liu February 25, 2012 Purpose: Eggshells are composed in part of calcium carbonate. Calcium carbonate reacts with an acid to produce carbon dio xide, water, and a salt. The calcium carbonate in the sample eggshell will be determined by means of an acid/base back-titration. Procedure: 1.Wash an empty eggshell with distilled water and carefully peel all the membranes from its inside. Place all of the shell in premassed breaker and dry the shell in the drying oven at 110 degree Celsius. for about 15 min. 2. Copy data and calculations tables from your teacher, as below. CaCO3 + 2HCl -----CaCl2 + CO2 + H2O ( Volume of acid added (L) ) (1.0mol/L) = moles acid added. Moles acid added - moles base added = moles acid that reacted. Moles of acid that reacted / 2 = moles CaCO3 present in sample. Final answer % CaCO3 3. Put exactly 5.0 mL of water in the 10.0 mL graduated cylinder. Record this volume in your data table (10.0 mL). Label the first pipet "Acid." To calibrate the pipet, fill it with LIU-2 water. Holding the pipet vertically, add 20 drops of water to the cylinder. Record the new volume of water in the graduated cylinder in the first data table under Trail 1. 4. Without emptying the graduated cylinder, add an additional 20 drops from the pipet. Record the new volume for Trial 2. Repeat this procedure once more for Trail 3. 5. Repeat Preparation steps 3 and 4 for the second pipet. Label this pipet "Base." |Trial |Initial |Final Acid|Initial |Final Base| | |Acid | |Base | | |1 |5.0 ml |5.8 ml |5.0 ml |5.8
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