SNC 2D Conservation of Mass Lab

SNC 2D Conservation of Mass Lab Name:______

Purpose: To determine if mass is conserved in a chemical reaction.

Theory: The Law of Conservation of Mass (or Matter) in a chemical reaction can be stated thus In a chemical reaction, matter is neither created nor destroyed. It was discovered by Antoine Laurent Lavoisier (1743-94) about 1785. Lavoisier first made this assumption and then verified it though numerous experiments. One critical idea necessary for this law's validity is the mass contained in “air” which might be released or absorbed in the chemical reaction. This idea of mass is consistent with “particle” theory – all matter whether solid, liquid or gas is made up of tiny particles.

Materials: balance, Erlenmeyer flask, small test tube or plastic pH vile, rubber stopper, barium chloride, sodium sulfate, sodium bicarbonate , acetic acid

Procedure; Part 1 - barium chloride (aq) and sodium sulfate (aq) 1. Pour a small amount of barium chloride into a small test tube. (half of a small test tube). 2. Pour an equal amount of sodium sulfate into the Erlenmeyer flask. 3. Gently place the test tube into the Erlenmeyer flask making sure that the solutions do not mix. 4. Place a rubber stopper on the Erlenmeyer flask. 5. Mass the Erlenmeyer flask and all its contents. Record this mass as the mass of the reactants. 6. Twist the Erlenmeyer flasks so the contents mix. Be careful not to loosen the rubber stopper. 7. Mass the Erlenmeyer flask again and record this mass as the mass of the products. 8. Place the new solution in a waste beaker and rinse your glassware with water.

Part 2. – acetic acid and sodium bicarbonate 1. Using a scoopula, place a small amount of sodium bicarbonate into the bottom of the rinsed Erlenmeyer flask. 2. Pour a small amount of acetic acid into the rinsed test tube. 3. Gently place the test tube into the Erlenmeyer flask making sure that the solutions do not mix. 4. Place a rubber stopper on the Erlenmeyer flask. 5. Mass the Erlenmeyer flask and all its contents. Record this mass as the mass of the reactants. 6. Twist the Erlenmeyer flasks so the contents mix. Be careful not to loosen the rubber stopper. 7. Mass the Erlenmeyer flask again and record this mass as mass of the products. 8. Place the new solution in a waste beaker and rinse your glassware with water. 9. Clean and put all your supplies away. Observations: Title: Name of the Mass of Mass of Evidence of a Reactants the the chemical change or Reactants Products that new products are (g) (g) formed

Part 1

Part 2

Discussion: 1. Describe each reactant as either ionic or molecular? barium chloride______sodium sulfate______sodium bicarbonate ______acetic acid ______

2. State whether each reaction is a synthesis, decomposition, single displacement, or a double displacement reaction.

3. Complete the word equation for the first reaction.

Barium chloride + sodium sulfate ______+ ______

4. Write the skeletal equation for this reaction.

______+ ______+ ______

5. Write the balanced chemical equation for this reaction.

______+ ______+ ______

6. Describe any difficulties with the execution of the procedure.

Conclusion: (What can we conclude about the mass of the reactants compared to the mass of the products?)