Experiment 4 Empirical formula of hydrated copper (II) sulfate PDF

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Experiment 4 Pre-Lab Title: Empirical formula of hydrated copper (II) Sulfate Objective: To test the accuracy and precision in determining the experimental empirical formula of copper (II) sulfate pentahydrate Hypothesis: The CuSO45H2O will be determined as the empirical formula of copper (II) sulfate. The chemical formula that reflects the relative number of atoms of each type in a molecule is the empirical formula. The mass is measured instead of moles when determining an empirical formula because there are no direct means to calculate the moles of an element compound. The amount of water that the sample will contain is 0.105g. The amount of copper that the sample will have been 0.075g. Finally, the amount of Sulfate that the sample will include is 0.115g. Each of the three constituents’ masses will be found by dehydrating the salt, the mass of copper by reacting the copper (II) sulfate with magnesium metal, and the mass of Sulfate by using the mass of copper. We must find the difference to isolate each component of copper (II) sulfate pentahydrate. Variable: Independent: Masses and moles of H2O, Cu, and Sulfate Dependent: the smallest number of moles of all the compounds measured, which determines the experimental empirical formula. Experimental Outline: 1. Find the mass of a clean and dry test tube by placing it in a tarred beaker. Then, add about 0.30 g of copper (II) Sulfate and mass the test tube with copper (II) sulfate pentahydrate. 2. Remove all the water with Bunsen burner for copper (II) sulfate pentahydrate. To get dehydrated. 3. After becoming heated, let the test tube cool down in the dry non-flammable container for about 5 minutes and take down the mass of the tube. 4. Measure the mass of anhydrous copper (II) sulfate in the test tube. Then, dissolve the copper (II) sulfate in about 3-5 cm of DI water. 5. Stir the mixture with the glass stirring rod gently until the copper (II) sulfate dissolves. 6. Polish and measure the magnesium. Cut the magnesium ribbon into smaller pieces. 7. Use the pieces of magnesium metal into three of the test tubes in a—100mL beaker of tap water. 8. Centrifuge and balance test tubes for 3000rpm for 1 minute. 9. After centrifuging, decant the liquid above the cooper in a waste beaker. 10. Put the sample test tube in a Clean and dry beaker and put in 140 degrees Celsius for about 15 minutes for all the samples 11. When the sample is done drying, measure the mass of the test tube and copper 12. After the experiment is complete, clean up the area and dispose of waste.

Chemical Hazards and waste: Proper gloves, goggles, and a lab coat are required to be constantly worn. Bunsen burners must be used with precaution. When you are done with using the Bunsen Burners, be sure to turn off the gas supply. Since Copper (II) sulfate pentahydrate is toxic and an irritant. It must be disposed of in the waste container. Likewise, 5M hydrochloric acid is corrosive and must be disposed of in the waste container. Handle all chemicals with care. Key Math Equations: Mass of water = mass hydrated copper (II) sulfate – mass of anhydrous copper (II) sulfate Mass Sulfate = mass copper (II) sulfate – mass copper Post Lab: Conclusion: The results from the experiment did not support the hypothesis. The experimental empirical formula calculated in the lab, based on average values for the ratio of water copper sulfate over the three trails, is CuSO46H2O. The relative standard deviation of the ratio of water is 1.9384. As for copper and sulfate is 0.3174078. The percent error of the ratio of water is 18.7940%. As for copper and sulfate is 11.8602%. The accuracy of the data is Inaccurate. The precision of the data based on the RSD values and percent errors is also inaccurate. The results differed from the expected value because the amount of copper to sulfate might not have been displaced from the centrifuge....