Preview

Colorimeter -Concentration of a Solution

Good Essays
Open Document
Open Document
862 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Colorimeter -Concentration of a Solution
Concentration of a Solution: Beer’s Law
The objective of this experiment is to determine the concentration of an unknown copper sulfate solution. You will be using the Colorimeter. In this device, red light from the LED light source will pass through the solution and strike a photocell. A higher concentration of the coloured solution absorbs more light (and transmits less) than a solution of lower concentration. The Colorimeter monitors the light received by the photocell as either an absorbance or a percent transmittance value.

You are to prepare five copper sulfate solutions of known concentration (standard solutions). Each is transferred to a small, rectangular cuvette that is placed into the Colorimeter. The amount of light that penetrates the solution and strikes the photocell is used to compute the absorbance of each solution. When a graph of absorbance vs. concentration is plotted for the standard solutions, a direct relationship should result, as shown. The direct relationship between absorbance and concentration for a solution is known as Beer’s law.
The concentration of an unknown CuSO4 solution is then determined by measuring its absorbance with the Colorimeter. By locating the absorbance of the unknown on the vertical axis of the graph, the corresponding concentration can be found on the horizontal axis. The concentration of the unknown can also be found using the slope of the Beer’s law curve.

PROCEDURE
1. Add about 30 mL of 0.10 M CuSO4 stock solution to a 100 mL beaker. Add about 30 mL of distilled water to another 100 mL beaker. 2. Label four clean, dry, test tubes 1-4 (the fifth solution is the beaker of 0.10 M CuSO4). Pipet 2, 4, 6, and 8 mL of 0.10 M CuSO4 solution into Test Tubes 1-4, respectively. With a second pipet, deliver 8, 6, 4, and 2 mL of distilled water into Test Tubes 1-4, respectively. Thoroughly mix each solution by inverting with a stopper. Clean and dry the stirring rod between stirrings. Keep the remaining

You May Also Find These Documents Helpful

  • Powerful Essays

    | [Solubility Product Constant] | Experiment 11 | | Molly McCabe | 4/18/2013 | | Data Tables: Part 1 and Part 2 Experimental Data: Standard | Calculated volume of copper sulfate in standards | Absorbance values | Blank | 0.0 mL | 0.0 | 1 | 1.25 mL | 0.094 | 2 | 3.75 mL | 0.065 | 3 | 2.50 mL | 0.099 | 4 | 3.50 mL | 0.129 | 5 | 5.00 mL | 0.187 | Collected Data | Test tube 1 | Test tube 2 | Test tube 3 | Test tube 4 | Test Tube 5 |…

    • 1473 Words
    • 6 Pages
    Powerful Essays
  • Satisfactory Essays

    The use of red dye #40 is common in various soft drinks today. The labels on these beverages do not specify how much dye we are consuming. We did this experiment to find out which soda uses the most dye. Using a spectrophotometer, we measured how much light is absorbed by various known concentrations of red dye. After collecting this data, a standard curve was made that correlated the concentration of red dye #40 to its absorbance rate. Our results showed that the sample of strawberry crush had the highest concentration of red dye #40 when compared to grape soda, diet cherry, and big red. After doing this experiment, one knows how much red dye #40 he or she is consuming when drinking these products.…

    • 342 Words
    • 2 Pages
    Satisfactory Essays
  • Powerful Essays

    Chem 103 Project Lab

    • 1372 Words
    • 6 Pages

    Beer’s Law helps explain the relationship between absorbance and thickness off a sample, and accordingly, the relationship between absorbance and the amount of solute in a solution. Forming a Beer’s Law plot is useful when having a solution…

    • 1372 Words
    • 6 Pages
    Powerful Essays
  • Good Essays

    investigation 20

    • 1002 Words
    • 5 Pages

    The experiment began by calibrating the spectrometer appropriately. By checking if the distilled water (a non-concentrated solution) produced a 0.000 absorbance, made sure that the correct data was collected. A sample solution of the cobalt (II) nitrate was transferred into a test tube and then diluted with distilled water to achieve the desired concentration of the cobalt (II) nitrate. For example, to achieve a 0.5 M cobalt (II) nitrate sample, add 5 mL of the cobalt (II) nitrate sample and dilute it with 5 mL of distilled water in a graduated cylinder. Following that, take the sample and place it in the spectrometer and record its absorbency.…

    • 1002 Words
    • 5 Pages
    Good Essays
  • Powerful Essays

    Chem Lab

    • 570 Words
    • 3 Pages

    2. Next, we measured our 80 ml of copper II sulfate and 20 ml of distilled water and combined them in a graduated cylinder.…

    • 570 Words
    • 3 Pages
    Powerful Essays
  • Powerful Essays

    Red 40 Lab

    • 2090 Words
    • 9 Pages

    Determining Red 40 Concentrations Using Absorption with Beer’s Law Introduction I like color and enjoyed learning about wavelengths and the spectrum of light, so I considered incorporating something related to that into my Internal Assessment. We also had just used concentrations in our Group 4 Project, so when I found an experiment that dealt with both of these I thought it was a great idea. This experiment is not completely original; the basic concept has been used multiple times. It uses Beer’s Law: · A is light absorbance · is “molar absorptivity with units of L mol-1 cm-1” · l is the length of the cuvette in centimeters · c is the concentration of the solution in mol L-1…

    • 2090 Words
    • 9 Pages
    Powerful Essays
  • Good Essays

    In order to complete the objective, the group used a Carolina Digital Spectrophotometer, unit M 201-1, which measures the quantity of light that solutions absorb. The spectrophotometer consists of a light source that shines through a prism which then shines through a…

    • 1159 Words
    • 5 Pages
    Good Essays
  • Powerful Essays

    Compare different methods for finding the concentration of copper(II) ions in solution. Could include redox titration, colorimetry, ion exchange followed by acid/base titration, gravimetric, use of an electrochemical cell.…

    • 4606 Words
    • 19 Pages
    Powerful Essays
  • Better Essays

    Beers Law

    • 879 Words
    • 4 Pages

    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)…

    • 879 Words
    • 4 Pages
    Better Essays
  • Satisfactory Essays

    Calibration Lab

    • 384 Words
    • 2 Pages

    We attempted to develop a method for determining the concentration of three different diluted copper (II) ion solutions. We also tried to determine the concentration of copper within a penny by dissolving it in nitric acid. We used a spectrometer to measure the %Transmittance of each and were able to convert it to it absorbance in order to plot it on our calibration curve. We used test tubes to contain the solution and set the spectrometers to 20, which were preset by the TA.…

    • 384 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Lab Report

    • 2156 Words
    • 9 Pages

    The entire experiment is based on the results from the calibration curve. The calibration curve is used to generate an equation that is then used to calculate molarity. This value is then converted to the desired unit, milligrams. So, to obtain the calibration curve data, two students began by preparing two solutions. The first was 100 mL of 1.0 x 10-3 M Fe(NO3)3, and the second was 100 mL of 0.10 M KSCN. Both solutions were made in 1.0 HNO3. The former solution was prepared using 0.0404 grams of Fe(NO3)3•9H2O on an analytical balance (calculations below). The latter solution was prepared using 0.97 grams of KSCN on a top loading balance (calculations below). Then, 1.0 mL of the iron nitrate solution was added to 100 mL of the KSCN solution and mixed. Being that the spectrophotometer (the instrument being used to measure absorbance) was already zeroed by the teaching assistant, the construction of the calibration curve could begin. To start, the cuvette was filled with the current mixture, placed into the spectrophotometer, and the absorbance was recorded. The cuvette was then emptied back into the beaker containing the entire solution, as not to skew the overall volume, and therefore the concentration.…

    • 2156 Words
    • 9 Pages
    Good Essays
  • Good Essays

    Simple Sugar Lab

    • 608 Words
    • 7 Pages

    substance to each test tube. then add 10 mL distilled water. swirl gently to mix.…

    • 608 Words
    • 7 Pages
    Good Essays
  • Good Essays

    Part 4: i) Place approximately 25 drops or copper (II) sulfate into a 100 ml…

    • 1621 Words
    • 7 Pages
    Good Essays
  • Powerful Essays

    The amount of copper obtained was 0.569 ppm ± 0.015 and for zinc we obtained 0.42 ppm ± 0.0027. For the slope and intercept of graph of copper absorbance for different concentration was 0.0755 as slope and 0.01289 as intercept and for zinc the slope was 0.337 and the intercept was 0.0421. In order to find the concentration of the unknown, the intercepts were assumed to be zero. The advantage of measuring many samples is that it gives a better fit for the curve that allows finding the slope and intercept. The solution containing both copper and zinc were run through the instrument to find the radiation absorbed using for copper the six element hollow cathode lamp containing some copper and same for zinc measurement. The disadvantage however is that if one sample has error, all other measurement follows the error and therefore the best fit is disturbed. The source of error for this experiment is most likely to come from the pipetting, where the last drop would fall before reaching the target…

    • 1026 Words
    • 5 Pages
    Powerful Essays
  • Good Essays

    1.Firstly I will measure 20ml of Copper Sulphate solution (CuSO4) in a measuring cylinder, for precise accuracy, and then pour the solution into test tube. I will place the test tube into a beaker and insulate the test tube, for minimum heat loss. (As shown in the diagram above.)…

    • 1131 Words
    • 5 Pages
    Good Essays