To Create Chalk by Reacting Calcium Chloride with Sodium Carbonate

Name:______

Date:______

Class period:______

Precipitate Lab

Objective

To create chalk by reacting calcium chloride with sodium carbonate.

Background

Calcium carbonate is an abundant chemical and is found in many different forms. Among these are limestone, a sedimentary rock formed from shells of mollusks. Calcium carbonate is manufactured in industry by the method in this lab. It is widely used as an antacid to neutralize the hydrochloric acid produced by the stomach, and also as a source of calcium to strengthen bones. Another form of calcium carbonate is chalk. Chalk is made for use as a gentle scouring powder. For that reason, it is used in toothpaste. Chalk is easy to make. In this lab you will react calcium chloride and sodium carbonate to make chalk.

Materials

Calcium Chloride (damp rid) funnel

Sodium Carbonate (pool supply store) 2 plastic cups

25 mL graduated cylinder digital scale

Coffee filter water

Stirrers

Procedure

Put safety goggles on before starting this lab!!

1. .Dissolve 3 grams of calcium chloride in 20 mL of water.(Stir until solute is all dissolved.)

2. Dissolve 6 grams of sodium carbonate in 20 mL of water.(Stir until dissolved)

3. Combine the solutions and stir them for a minute or so

4. Fold the filter paper into fourths. Make a cone with the three sides together and one side separated. Place the filter paper into the funnel.

5. Pour the mixture from the beaker into the funnel. Place the cup underneath to collect the liquid.

6.The white solid chalk or CaCO3 collects on the filter paper in the funnel, this is the precipitate.

7. The salt or sodium chloride dissolves in the water and passes through the filter paper, this is the filtrate.

8. Repeat the filtering process several times to collect the most precipitate.

9. After filtering is finished let filter paper dry until the next class period.

10. Clean up , rinse out cups and dry them, put everything in its designated place.

11.Wash your hands

Equation: CaCl2 + Na2CO3  2NaCl + CaCO3

. calcium chloride sodium carbonate sodium chloride calcium carbonate

1.What evidence did you see that a reaction occurred when you combined the calcium chloride and sodium carbonate?

A white substance formed in the beaker, a precipitate.

2. List the reactant compounds-names and formulas.

CaCl2 - Calcium Chloride

Na2CO3 - Sodium Carbonate

3. List the product compounds- names and formulas.

2NaCl -Sodium Chloride

CaCO3 - Calcium Carbonate

4. What kind of mixture was the filtrate ( homogeneous, heterogeneous, solution or colloid?)

Homogeneous and solution

5. How did the particles of the precipitate compare to those of the filtrate?

The particles of the precipitate were larger than those of the filtrate as they collected on the filter paper.