Lab: STOIOCHIOMETRY OF A PRECIPITATION OF REACTION
By: Ruth Pierre
6/1/15

PURPOSE
Stoichiometry is a section of chemistry that involves using relationships between reactants and products in a chemical reaction to determine desired quantitative data. Stoichiometry means the measure of elements. In order to use stoichiometry it is important to understand the relationships that exist between products and reactants and why they exist, which require understanding how to balanced reactions. The purpose of this experiment is to predict the amount of product produced in a precipitation reaction using stoichiometry. This experiment will also to determine the actual yield versus the theoretical yield in order to calculate the percent yield.

MATERIALS * Distilled water * Paper towels * Small paper cup * Coffee cup or mug * Beaker 100 ml glass * Funnel * Cylinder 25 ml * Goggles for safety * Scale Digital-500g * Weighing boat plastic * CaCl2·2 H2O-Calcium Chloride, Dihydrate - 2.5 g * Filter Paper 12.5-cm, Na2CO3 -Sodium Carbonate - 2 g

PROCUDURE 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. 7. Swirl the contents of