Lab7 Report

a) The refractive index (μ) of water is found to have the values 12.9,12.5,12.3 and 11.8.Calculate the standard deviation for the refractive index of water.

5. How do you calculate the Numerical aperture of an Optic fiber? Find the numerical aperture '0' of a 1.5m plastic optical fiber, if the distance from tip to surface is 5cm and the light radius is 3.5cm?

A protein’s concentration can be determined spectrophotometrically by mixing it with an indicator called a Bradford reagent and measuring the amount of light absorbed by the protein. Use the plot below to determine the mass of protein (in micrograms, μμg ) in 100.0 mL of the solution if its absorbance is 0.398. A.  52 B.  3.1 C.  2.4 D.  0.52 E.  0.031

10. The concentration of haemoglobin in a blood sample was determined by spectrophotometry. A standard curve of the absorbance at 412 nm of several solutions of known haemoglobin concentrations was created. The data for the standard curve is shown below. a. Calculate the linearity coefficient (r), y-intercept and slope. b. What is the concentration (in ug/mL) of haemoglobin in your sample if the absorbance obtained at 412 nm was 0.303? Absorbance Concentration of standard solution (pg/ml) (412nm) 0.069 1 0.113 2 0.201 4 0.377 8. 0.730 16

Of particle size techniques, which technique can identify the 3-D dimensions of the particles? O The Andreason pipette technique O The scanning Electron microscopy O Optical microscopy O The sieving method

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What is the structure of function of this molecule. a w x x x x x x x x x b -1 2 3

What is the significance of whether the fluorescent substance in fluorescent tubes has a short or long phosphorescence?

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Spectrophotometry and Beer's Law 4. A solution has 23.6% transmittance in a cell with a path length of 1.00 cm. If the material responsible for the absorption of light has a molar absorptivity e = 36.2 (L/mole-cm) at the wavelength used, calculate the concentration of this solution in mole/L. (Show all work.) M

Data Set Exp.5 Use the following data to determine the mass percent of the active ingredient in Aspirin a) Preparation of solutions: volume of salicylic acid volume of FECL3 solution SA1 1ml 9ml SA2 3.5ml 6.5ml SA3 6.5ml 3.5ml SA4 1ml 9ml The concentration of salicylic acid= 0.000725M b) Preparation of "STOCK ASA UNKNOWN" The mass of aspirin= 0.135 g The volume of stock solution of aspirin= 100ml The dilution factor for the stock solution= 50/2 Molar mass of SAS = 180.157 g/mole c) Measurements of Absorbance: Solution Absorbance SA1 0.154 SA2 0.524 SA3 0.789 SA4 0.989 The unknown sample 0.259

Why do we need to prepare a standard curve before we can use Beer's Law to determine the concentration of a solution? O We don't have to create a standard curve so long as we choose the appropriate wavelength. Because the standard curve tells us the absorbance of our sample Because the standard curve is used to determine the extinction coefficient Because the standard curve indicates what wavelength to set the spectrophotometer to

Question 10 Which of the following statements is false about single beam absorption instruments? A Test tube is used as sample holder B) Tungsten bulb is used as a source Photovoltaic cell as detector Beam splitter is used to get parallel beam

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