CHEM
LabReport#6-1

6 obtained a test tube filled with an unknown

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6. Obtained a test tube filled with an unknown concentration of CuSO 4 *5H 2 O. 7. Measured the percent transmittance of the unknown. Data and Calculations: Molarity of CuSO 4 *5H 2 O Calculations mL from Original Water added 0.500 M ----- 20mL 0.200 M 8mL 12mL 0.100 M 4mL 16mL 0.050 M 2mL 18mL Standard Solution Absorbance Rounded Solution Absorbance Rounded 0.500 M -log(.40) = 0.3979 0.40 0.500 M -log(.42) = 0.3768 0.38 0.200 M -log(.71) = 0.1487 0.15 0.200 M -log(.70) = 0.1549 0.15 0.100 M -log(.86) = 0.0655 0.07 0.100 M -log(.86) = 0.0655 0.07 0.050 M -log(.89) = 0.0506 0.05 0.050 M -log(.90) = 0.4576 0.05 % of transmittance for the unknown was: _61__ Absorbance for the unknown was: -log(.61) = _0.21___ Standard Solution % Transmittance 0.500 M 40% 0.200 M 71% 0.100 M 86% 0.050 M 89% Solution % Transmittance 0.500 M 42% 0.200 M 70% 0.100 M 86% 0.050 M 90%

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Course:1251L/25 Experiment: Creating Solutions of Standard Molarity Laboratory Report # 6 Line of fit absorbances: 0.050 = 0.04 absorbance 0.100 = 0.08 absorbance 0.200 = 0.15 absorbance 0.500 = 0.39 absorbance % error: 0.500 = (.38-.40)x100 = 2% 0.200 = (.15-.15)x100 = 0% error 0.100 = (.07-.07)x100 = 0% of error 0.050 = (.05-.05)x100 = 0% error Conclusion: To create the 0.500M solution of CuSO 4 *5H 2 O we measured 2.4969 grams of CuSO 4 *5H 2 O and added 20mL of water. We mixed the water and the solid by transferring the mixture back and forth beakers to ensure it was completely dissolved. Our standard was close to the original but it was still off by two percent. Our dilutions were very close to the originals. According to the absorbance levels they were right on target. This was due to the fact we started over many times after a lot of errors. In Data and calculations I displayed the calculations we used for our dilutions. If a solution has a higher concentration the absorbance is least because less light can pass through the test tube. y = 0.7036x + 0.0432 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 Absorbance Solution Concentration
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