Lab Report: Law Of Conservation Of Mass 1r3v6x

Purpose:

To and observe the Law of Conservation of Mass.

Hypothesis:

The mass of the reactants will be the same as the mass of the products.

Apparatus: test tube rubber stopper copper (ll) sulfate balance hydrochloric acid scoopula

Erlenmeyer flask graduated cylinder sodium hydroxide beaker sodium bicarbonate

Method: PART 1: 1. 10mL of copper (ll) sulfate was poured into the flask. 2. 10mL of sodium hydroxide was poured into the test tube. 3. The test tube was gently placed into the flask without letting the two chemicals mix. 4. The rubber stopper was placed firmly on the flask. 5. The entire apparatus was weighed. 6. The flask was gently inverted and the two chemicals were mixed. 7. The reaction was observed. 8. The final products were weighed. PART 2: 1. 15mL of hydrochloric acid was poured into the test tube. 2. 1 scoop of sodium bicarbonate was placed into the beaker. 3. The test tube was carefully placed into the beaker and the apparatus was massed. 4. The acid was poured into the beaker. 5. The reaction was observed. 6. The test tube was placed back into the beaker and the beaker was massed. Observations: REACTANTS Part

Reactant names copper (ll) sulfate

• •

Transparent with a blue tint. liquid

Sodium hydroxide

• •

Transparent and clear (no colour). liquid

hydrochloric acid

• • •

Transparent (clear) vinegar scent liquid

sodium bicarbonate

• • • •

White opaque powder solid

1

2

Describe each reactant

Total Mass

277.7g

222.2g

PRODUCTS Part

Describe what you observed when the reactants were mixed

Total Mass

• • •

Precipitate was present translucent solution had a bluish tint

277.7g

1

• •

Bubbles, a gas was produced there was white powder left at the bottom of the beaker that did not dissolve. A substantial amount of liquid was gone because of the formation of gas. Vinegar scent

221.7g

2

• •

A gas was produced so mass was slightly lower. CO2 weighed 0.5g.

Conclusion: Since, in both part 1 and 2, the mass of the reactants and the mass of the products was the same, therefore, according to the Law of Conservation of Mass, no mass can be gained or lost during a chemical reaction. Discussion: This lab was done to the Law of Conservation of Mass. Two chemical reactions were observed during this lab and the results proved the Law of Conservation of Mass to be correct. The reactants mass was equal to the products mass in both reactions. Although, in the second part of the lab, a gas was produced during the reaction and the mass of the gas was released into the atmosphere. That mass was not lost, it was just no longer present in the solution. In conclusion, the lab verified that mass can not be created or destroyed during a chemical reaction. Discussion Questions 1. The evidence that a chemical change occurred in part 1 was that a precipitate was present. 2. The evidence that a chemical chance occurred in part 2 was that a gas was produced. 3. a) copper (ll) sulfate + sodium hydroxide -------> sodium sulfate + copper (ll) hydroxide b) CuSO4 + 2NaOH ------> Na2SO4 + Cu(OH)2 4. a) Sodium chloride, water, and carbon dioxide were the three products in part 2. b) Carbon dioxide left the beaker. c) hydrochloric acid + sodium bicarbonate ------> sodium chloride + water + carbon dioxide d) HCl + NaHCO3 -------> NaCl + H2O + CO2 5. A chemical reaction occurs when the log is burned. As the log is burning a gas is being produced taking some of the mass with it. The mass of the reactants and the products are the same but one of the products is not present, resulting in a lower mass. 6. The mass of the solution was 30g. 7. A mass of 20g of gas was produced.

8. Bread rises when it is baked because yeast converts some glucose molecules in bread dough into carbon dioxide and ethanol. The carbon dioxide being released causes the bread to rise. I think that the mass of the bread would be lower than the original total mass of the ingredients because a gas is released during baking causing the final product to weigh less. 9. a) C + Fe2O3 ---------> Fe + CO2 b) 3C + 2Fe2O3 ---------> 4Fe + 3CO2 c) 60.6g of carbon dioxide was produced. Pre Lab: In your own words state the Law of Conservation of Mass. In a chemical reaction, the reactants has the same mass as the products. Mass cannot be created or destroyed in a chemical reaction. Define reactants: Chemicals that react in a chemical equation, they are on the left side of a chemical equation. Define products: Chemicals that are produced in a chemical reaction, they are on the right side of a chemical equation. Reference

Adam-Carr, C., Gabber, M., Hayhoe, C., Hayhoe, D., Hayhoe, K., & Sanader, M. (2010). Science perspectives 10. (1st ed. ed., Vol. 1). Toronto: Nelson Education. A Chemical Reaction Problem. (n.d.) Retrieved October 3, 2012 from http://www.chymist.com/chemical%20rxns%20problem.pdf