The purpose of this experiment is to apply Beer’s Law by analyzing samples provided by Q laboratory to determine their absorbance and prepare a Beer’s law plot. Molarity of these samples was also calculated to determine concentration and percent error rate. Students also analyzed the concentration of blue dye #1 to determine the concentration of blue dye #1 in a commercial blue dye drink. Procedure
Exercise #1
Step #1: Convert %T (Table 1) to absorbance and prepare a Beer’s law plot using the data.
Step #2: Determine the concentration of M of the samples in table 2: A=ebc
A= 2-log(%t)
B= 1.0 cm
Solve for E
E=1875
(0.36) / (1875*1) = 1.92 x 10-4 m/L Molarity for all five slots
Step #3: Determine the percent error.
3.0 X 10-4 – 1.92 X 10-4 X 100 = 36%
3.0 X 10-4
Step #4: Determine if batch 021015 meets legal requirements
Is it in the range of 2.85x10-4 and 3.15x10-4??
Exercise #2
Step #1: Fill a 100ml beaker with distilled water and add 20 drops of blue dye #1 and stir. Add more drops of blue dye to solution if it is not darker than your commercial dye. (I added an extra 20 to make mine darker) This gave me a concentration of 5.2x10-4. Record concentration
Step #2:Place a 12 well strip on a white sheet of paper and number 1-10 starting from the left.
Step #3: Using the 1mL fine tip pipet add the appropriate number of drops of blue dye solution to each well. (refer to data table 1 in lab assistant section)
Rinse pipet thoroughly with clean water by squeezing water in and out of bulb 6-10 times.
Step #4: Using the 1mL fine tip pipet add the appropriate number of drops of distilled water to each well. (Refer to data table 1 in lab assistant section)
Step #5: Place a strip of clear tape over the wells to ensure no spillage will occur.
Step #6: Use the data table in the lab report to record calculations of Molarity of blue dye.
Step #7: Fill 1mL fine tip pipet with
References: List all your references. Be sure to use the APA format. 1. Hands-On Labs, Inc. (n.d.). A laboratory manual of small-scale experiments for the independent study of General College Chemistry. Englewood, Colorado: Hands-On Labs, Inc.