Question

Can someone rewrite this in past tense, passive voice?

To begin the first experiment, you must first calibrate the Spectrophotometer. First transfer water into the cuvette, wipe cuvette and place into the spectrophotometer, then calibrate the instrument. Once calibrated construct a calibration curve for the food dye dilutions of red, yellow, and blue. Begin with transferring the color dilution series to the cuvettes and wipe the cuvettes. Place a cuvette into the spectrophotometer and enter the desired analytical wavelength, in this case we started with blue, so we entered 628 nm, and press go. Measure and save the absorbance for each sample in the color dilution series. Remember when doing so to save the absorbance values in the “current data table”. After measuring the absorbance of each sample in the color dilution series, create a calibration curve with the saved data. Enter the slope for the best fit line into your notebook. Repeat for the following color dilution series. Next to determine the concentration of the unknown sample (x) we repeat the process of transferring the unknown sample into cuvette and recording the absorbance, using the correct analytical wavelength. Finally, calculate the concentration for the unknown sample using the calibration curve.

            In the second experiment prepare colored dye mixtures in a clean test tube. Using red, blue, and yellow make 3 mixtures that are different be sure to stir mixtures. Using the concentration of each colored solution, calculate the theoretical concentration for each color in the mixture and record your data in your notebook. In the next part in experimental determination of dye concentration use a pipet as you did in the first experiment, make sure you calibrate the instrument first and then measure the absorbance of each mixture using the correct analytical wavelengths given. Use the calibration curve and determine the experimental concentration of each color dye in the mixture and record each concentration. Calculate the absolute and percent errors, then evaluate the accuracy of each theoretical concentration. In the last experiment there is an unknown sample of a mixture of red and yellow food dyes. Repeat the process of measuring the absorbance of this mixture using the correct given wavelengths. Once recorded use the molar absorptivities given and calculate the concentration for each colored dye in the mixture and record in your notebook.

Answer 1

In the first experiment, spectraophotometer was caliberated. At first, cuvette filled with water was placed in the spectrophotometer to calibrate the instrument. Thereafter, caliberation curves for red, yellow and blue dyes were constructed. The color solutions were transfered into cuvettes and cuvettes were cleaned. Cuvette was placed into spectrophotometer and desired wavelength was entered. The sequence begun with blue with a waveelength of 628 nm, the absorbance value was saved. The procedure was repeated for each dye solutions. Once the absorbance valuees were recorded, a calibration curve was created from absorbancee data. The concentration of an unknown solution the whole process was repated and absorbance was recorded. Afterwards, the concentration of unknown was calculated from the calibration curve.

For the second experiment, Three different coloured dye mixtures were prepared in three different test tubes, the mixtures were stirred properly. The concentration of each colour in the mixture and recorded. In next stage, the concentration of dye was experimentally determined by the method of first experiment. As a precaution, calibration of instrument was done in prior. Once the values were recorded, percentage and absolute errors were determined to quantify the accuracy of theoretical concentration.

Last experiment was carrried out using an unknown sample of a mixture of red and yellow dye. The whole above procedure were recorded using correct wavelengths. After obtaining absorbance values, concentration were calculated by using molar absorptivities and recorded in the notebook.

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