Part C: Dilutions Part C1: Basic Dilutions During scientific experiments, it is often necessary to dilute the solution provided (the stock solution). For example, such a dilution might be made to reduce chemical concentrations so the rate and intensity of reactions can be controlled. A stock (100%) dye solution and distilled water will be used in this lab. How would you go about preparing 10 ml each of 75%, 25%, and 10% solution from an available stock solution of 100%? The algebraic equation C1V1 = C2V2 provides our tool to answer this question, where C1 = concentration (%) of solution V1 = volume (ml) or stock required to prepare the solution (you typically are solving for this variable) C2 = concentration (%) of dilution you wish to prepare V2 = volume (ml) of dilution you wish to prepare Procedure Use the algebraic equation to determine volumes of 100% stock (ml) and distilled water (ml) required to create 10 ml each of 0%, 10%, 25% and 75% dilution. Record your answers in Table 2.4. 2.4 Volumes Needed to Prepare Dilutions Concentrations C2 10% 25% 75% – Volume of stock solution (ml) - V1 Volume of water (ml) Total volume of dilution (ml) - V2 Obtain 3 test and a test tube rack Prepare the three dilutions from Table 2.4 by pipetting the correct amount of stock in the test tube and then diluting the stock with the correct amount of distilled water. first There should be the same amount of liquid in each test tube when you are finished Obtain 5 cuvettes on a cuvette rack Transfer distilled (0% dye solution) to the first cuvette up to about ¾ full. Distilled water is used as a blank solution to calibrate the spectrophotometer One at a time and in order of increasing concentration, transfer enough of the other 4 solutions so that each cuvette is approximately ¾ full Set the spectrophotometer to a wavelength of 450nm Read the % light transmittance for each dye solution you prepared and record your results in Table 2.5
Part C: Dilutions Part C1: Basic Dilutions During scientific experiments, it is often necessary to dilute the solution provided (the stock solution). For example, such a dilution might be made to reduce chemical concentrations so the rate and intensity of reactions can be controlled. A stock (100%) dye solution and distilled water will be used in this lab. How would you go about preparing 10 ml each of 75%, 25%, and 10% solution from an available stock solution of 100%? The algebraic equation C1V1 = C2V2 provides our tool to answer this question, where C1 = concentration (%) of solution V1 = volume (ml) or stock required to prepare the solution (you typically are solving for this variable) C2 = concentration (%) of dilution you wish to prepare V2 = volume (ml) of dilution you wish to prepare Procedure Use the algebraic equation to determine volumes of 100% stock (ml) and distilled water (ml) required to create 10 ml each of 0%, 10%, 25% and 75% dilution. Record your answers in Table 2.4. 2.4 Volumes Needed to Prepare Dilutions Concentrations – C2 10% 25% 75% Volume of stock solution (ml) - V1 Volume of water (ml) Total volume of dilution (ml) - V2 Obtain 3 test and a test tube rack Prepare the three dilutions from Table 2.4 by pipetting the correct amount of stock in the test tube first and then diluting the stock with the correct amount of distilled water. There should be the same amount of liquid in each test tube when you are finished Obtain 5 cuvettes on a cuvette rack Transfer distilled (0% dye solution) to the first cuvette up to about ¾ full. Distilled water is used as a blank solution to calibrate the spectrophotometer One at a time and in order of increasing concentration, transfer enough of the other 4 solutions so that each cuvette is approximately ¾ full Set the spectrophotometer to a wavelength of 450nm Read the % light transmittance for each dye solution you prepared and record your results in Table 2.5
BSC%201010C%20Lab%20Manual%202015.docx