Investigation: Conservation Of Mass (Lab Conservation Of Mass)

Investigation: Conservation of Mass

Question Is there a change in mass after a chemical reaction occurs?

Hypothesis (write a hypothesis for this investigation)

Materials goggles, 2 small test tubes, flasks, iron (III) chloride solution, sodium hydroxide solution, sodium bicarbonate, hydrochloric acid, graduated cylinder, balance, stopper, tongs

Procedure Part A: Iron (III) chloride and sodium hydroxide 1. Practice holding the empty test tube with tongs and sliding it into an empty Erlenmeyer flask. Seal the flask to check that the test tube fits and that the stopper forms a tight seal. 2. Make observations of the substances before and after the reaction. 3. Measure 5mL of sodium hydroxide solution in the 10mL graduated cylinder. Pour this solution into the flask. 4. Measure 5mL of iron (III) chloride solution. Pour this solution into the test tube. 5. Tilt the flask and carefully slide the test tube into it. Do not allow the test tube’s contents to spill. 6. Seal the flask with the stopper. 7. Place the flask on a balance and determine the mass of the flask and the chemicals. 8. Mix the contents in the flask by tilting the flask so that the iron (III) chloride solution mixes with the sodium hydroxide solution. 9. Measure the mass of the flask again. 10.Calculate the change in mass. 11.Record your data on the class results list.

Part B: Sodium bicarbonate and hydrochloric acid 1. Using the balance measure out 1 g of sodium bicarbonate and place it into a flask. 2. Make observations before and after the reaction. 3. Measure out 15mL of hydrochloric acid and place it into a test tube. 4. Place the test tube into the beaker. Do not put a stopper on the flask. 5. Place the flask on a balance and determine the mass of the flask and the chemicals. 6. Mix the contents in the flask by tilting the flask so that the sodium bicarbonate mixes with the hydrochloric acid. 7. Measure the mass of the flask again. 8. Calculate the change in mass. 9. Record your data on the class results list.

Results Reactants Description Total Description of Total of Reactants mass products mass before after Iron (III) chloride solution

Sodium hydroxide solution

Sodium bicarbonate

Hydrochloric acid

Discussion 1. Answer “Analyze and Evaluate” questions a-j on page 229 in your textbook. 2. Write the word equations to describe the two reactions. 3. State the Law of Conservation of Mass and explain why it is difficult to apply to a reaction in which a gas is produced? Iron (III) chloride and sodium hydroxide

Class Results Investigation – Conservation of Mass

Name(s) Mass change (+ or -) 1.

Average change Sodium bicarbonate and hydrochloric acid

Class Results Investigation – Conservation of Mass

Name(s) Mass change (+ or -) 1.

Average change