04/09/12 Chemistry I B Ms. Norton Introduction/Pre-laboratory Assignment: 1. Write out and balance each of the following equations. A. CuSO4 + Fe Cu + FeSO4 B. 3CuSO4 + 2Fe 3Cu + Fe(SO4)3 2. If Iron (III) Sulfate were formed, what mass of Copper would be expected and what is the limiting reagent? C. 2. 26 g Cu D. Fe 3. If Iron (II) Sulfate were formed, what mass of Copper would be expected and what is the limiting reagent? E. 2. 8 g Cu F. CuSO4 Driving Question: What compound is formed when you add 7 g of CuSO4 to 2 g of Fe?
Goal: To correctly identify what compound is formed and how close it is to the theoretical yield. Materials: * Safety Goggles * Lab Apron * Two 250-mL Beakers * Ring Stand * Ring * Wire Gauze * Bunsen Burner * Balance * Stirring Rod * Matches * Water (H2O) * Iron (Fe) * Copper (II) Sulfate (CuSO4) Chemical Names: * Water (H2O) * Iron (Fe) * Copper (II) Sulfate (CuSO4) * Iron (II) Sulfate (FeSO4) * Iron (III) Sulfate (Fe2(SO4)3) * Copper (Cu) * Methane (CH4) * Copper (II) (Cu2+) * Iron (II) (Fe2+) * Sulfate (SO4) Procedure: I. Place 7. 0g of copper (II) sulfate in a beaker. II. Add about 50mL of water to the beaker III. Light the Bunsen Burner and place it under the beaker. Adjust the burner so the hottest part of the flame touches the bottom of the beaker. IV. Carefully heat and stir the mixture in the beaker. The solution should be hot, but not boiling. After all of the crystals have dissolved, remove the beaker form the heat. V. Add 2. 00g of iron filings slowly to the hot copper sulfate solution while stirring. Record observations. VI. Allow the beaker to cool for 10-15 minutes.
VII. Pour off (decant) the solution into a different beaker. Pouring the solution down a stirring rod is recommended. Make sure not to disturb the copper in the beaker. VIII. Add a small amount of water (10-15mL) to the copper and stir. IX. Let the copper settle to the bottom of the beaker and decant again. X. Dry the copper as your teacher directs and determine its mass. Record this mass. XI. Calculate the percent yield by using the theoretical yield that you determined in the pre-lab. Observations: Adding Iron to Copper (II) Sulfate Got very hot * It started sizzling * Made greenish/turquoise bubbles * A brownish sludge formed These were all chemical reactions that took place. The reason that this is known is because of table 7. 1 on page 219 in the textbook. Data: | Yield| Percent Yield| Theoretical:| 2. 28 g Cu| 100 %| Actual:| 2. 13 g Cu| 93. 4 %| Data Analysis: When weighing the mass of our product you get 2. 13 grams. Also when you figure out the percent yield you get 93. 4%. Conclusion: I. The limiting reactant was 2. 28 g Cu. Because iron is the limiting reactant.
I know this because when the equation is done iron ends up being the limiting reactant. II. So iron would be the limiting reactant. You have unreacted iron that will mess up the weight. III. So the impurities were washed away and the experiment is contaminated. IV. It didn’t have anything to do with the reaction because it was a spectator ion. V. CuSO4 + Fe Cu + FeSO4 There are two main errors that could happen in this lab. The first being human error when weighing the elements. This would result in more reactants which would cause more products and a misreading in your percent yield.
The second would be heating the Copper (II) Sulfate containing water is heated to high which would cause unreacted Iron which would screw up the percent yield. I had a lot of strengths and weaknesses. I had a strong grasp on what we learned and the lab was very easy. One of my weaknesses was allowing others to participate in the lab. I like doing everything by myself so if it is screwed up I blame myself and not others. I need to work on allowing others to participate. This information is useful because it will be very useful in later chemistry. It also helps my knowledge to maximize the output in an equation.