ABSTRACT In the “Density, Accuracy, Precision and Graphing” experiment, the purpose was to determine the density of water and the concentration of a saline solution as well as to compare the accuracy and precision of a graduated cylinder and a graduated pipet. Based on the instructions of the lab manual, Fundamentals of Chemistry, the experiment was performed in three parts, Part A: Density of Water-The density of water was calculated by measuring the mass of three different volumes: 10mL, 30mL and 50mL. Part B: Accuracy and Precision was performed using a 100mL beaker, 10mL graduated pipet and deionized water. The experiment was performed three times; each time, 10mL of water was added to the beaker and recalculated. Part C: Density of Sodium Chloride (NaCl) Solution, a sample of NaCl was obtained and measured using a 100mL beaker and a 10mL pipet to determine the concentration of the solution.
(0.050) (0.1) = 0.0083 moles b. Pour 8.3 mL of the stock solution to get the amount needed. c. Measure out 8.3 mL in a graduated cylinder 8. Exercise 8: a. 41.8 mL are used b. 0.00079 moles EDTA4- c. 0.00079 moles ZnI2 d. 0.0517 grams of ZnI2 are in the sample e. 0.0517/0.237= 21.8% f. Error Is 6.34% Lab Report: Part 1: In this lab we used the following supplies: * Zinc Iodide * Na2H2EDTA(s) * Calmagite indicator solution * pH 10 buffer solution * 6M Acetic Acid * Unknown Zinc Compound The main purpose for this part of the lab was to determine the amount of zinc ion in a sample of ZnI2 by titration.
Glen Mings CHEMISTRY 1 SUMMER 1 Experiment 9 Report Submitted: June 28, 2015 Title: Determination of Water Hardness Using a Titrator Purpose: To find out how “hard” my tap water is; specifically the concentration of calcium carbonate in ppm, and compare it to the four classifications. Procedure: Using a titrator, I measured how much EDTA solution it took to bond all of the Ca2+ ions, which was determined when the EBT turned from purple to blue. And since the reaction is 1:1 stoichiometric, we can assume that the moles of EDTA used equal the moles of calcium ions. Data Collected: | Initial EDTA volume | Final EDTA volume | Total volume of EDTA used | Trial 1 | 7.0 ml | 6.6 ml | 0.4 ml | Trial 2 | 6.6 ml | 6.3 ml | 0.3 ml |
We didn't make any mistakes. Possible errors we could have made throughout the lab would be: not letting the water fully evaporate, not measuring properly, burning the mixture, or even being careless and not doing things in order and as it was said. Discussion of Sources of Error- Our percent yield number was 99.1%. As I had said, we did everything pretty accurately with no major mistakes. It is possible that when we weighed the copper, it could have not been fully dry.
Procedure: Refer to Chemistry Lab Manual pp. 33-35, 37. Results: The density of the yeast-sugar solution on day 1 was 1.05g/mL. On day 2, the density of the solution had dropped down to 1.00g/mL. We found the mass of our pure alcohol to be 10.23g.
For “the cell” of 20% sugar solution in the 1% sugar solution I predict that the weight will stay the same as well just because it is in a less concentrated solution as “the cell”. Conclusion: The results were very surprising, it was not what I expected at all. My prediction of the cell of 1% sugar solution in the 1% sugar solution was correct. The cell weighed the same after the twenty minutes. This cell was placed in a isotonicity enviroment.
Initial Concentration Chemical Mass of Graduated Cylinder (g) Mass of Sugar (g) Molar Mass (g) Moles in Graduated Cylinder Total Volume (L) Molarity (mol/L) Sugar (C12H22O11) 16.6 10 342.29 .29 .1 .29 Data Table 9. Dilution Series Dilution Volume (mL) Mass (g) Density (g/mL) Initial Concentration (M) Volume Transferred (mL) Final Concentration (M) 0 25.0 mL 25 25 0 mL 0ml 1 25.0 mL 10 10 .29 2.5 mL 5.4M 2 25.0 mL 15 40 .435 4.5 mL 6.8M 3 25.0 mL 20 45 .58 3.0 mL 9.4M 4 25.0 mL 25 50 7.25 6.0 mL 11.2M Data Table 10. Molarity vs. Density Molarity vs. Density molarity is the concentration of a solution given in gram moles of solute per liter of solution. Density is the degree of compactness of a substance. Questions: How would you prepare 10 mL of a 0.25M HCl solution if 1M HCl was available?
The final crude product yield was 0.91g and the pure product yield was 0.36g. Error may have occurred during the extraction phase. Although I extracted twice with Sodium Chloride, if waste was not completely removed, it would affect the purity of the product. The distillation process may have also affected the pure product. The lab manual recommended that 0.5mL of waste be removed during distillation; otherwise it would affect the purity of the product.
When an indicators color changes it shows the presence of an organic compound. The purpose of using distilled water as one of the substances is that it is the control so you can see the differences. Also, in the substances distilled water was mixed in with them. The control group in part C is distilled water. The purpose of washing the test tubes thoroughly is so the chemicals don’t cross contaminate and affect the outcome of another section of the lab.
Samantha Monette Lab Section E Wednesday 10:00-12:50 p.m. Bromination/Debromination of Cholesterol Abstract: The purpose of this experiment was to purify commercial cholesterol. The commercial cholesterol was brominated using bromine as the reagent. After the compound was cooled and vacuum filtrated, dibromocholesterol was obtained. To purify the dibromocholesterol, zinc was added as the reagent. After a series of washes to remove any impurities, the compound was dried and decanted, cholesterol was synthesized.