Juliana Park Mayumi Tamada CHEM 111B LAB/ M-F 1-4PM 15 August 2012 Spectroscopy Lab Introduction In this lab, the molar absorptivity of the complex FeLn2+ will be determined by using the absorbance of the complex and its concentration. The absorbance will be found by using a spectrophotometer. For the next part of the lab, the formula of the complex will be determined by also using the volume of ligand and the absorbance again. Experimental There are two different parts to the experiement. In the first part, five 100 mL flasks of 5 mL ligand solution, 5 mL 2 M sodium acetate, 4 mL 3 M NH2OH, and 1-5 mL Fe2+ solution are diluted with water.
Record the readings of the three instruments at eight different speed settings of the tunnel: 15, 20, 25, 30, 35, 40, 45, & 50. 4. Plot two calibration curves with pressure transducer reading as the abscissa and micromanometer reading as the ordinate for the first, and micromanometer versus scannivalve as the second. Convert micromanometer data to read as total pressure in SI units [Pa]. 5.
Repeat the titration until there are two titres within 0.1cm3 of each other. Record results in a suitable table. Results: Rough Titre: 7.653 First Run: 6.553 Second Run: 6.453 Third Run: 6.553 Calculations: During the titration, iron(II) ions are oxidised to iron(III) ions and manganate(VII) ions are reduced to manganese(II) ions. The equation is as follows: 5Fe2+(aq) + MnO4-(aq) + 8H+(aq) ? 5Fe3+(aq) + Mn2+(aq) + 4H2O(l) The above equation shows that one mole of manganate(VII) ions reacts with 5 moles of iron(II) ions in acid solution.
Find the mass of the 5 dry pennies, then record the data. 2. Add 5 more pennies to the first group for the mass of 10 pennies, record mass. 3. Repeat step two, then continue adding 5 dry pennies each step to balance until you have used all 30 pennies 4.
Materials and Methods Part 1 For the cation elimination test first 10 drops of potassium, iron (III), zinc (II), copper (II), and cobalt (II) were added to 5 centrifuge tubes and the color was recorded. Then for the metal hydroxide test, 6 M NaOH was added drop wise till a precipitate was formed. Each solution except potassium formed a precipitate, so then 10 additional drops of NaOH were added to the remaining solutions. Tubes were cleaned with distilled water and 6 M HCL. Next was the ammonia test 10 drops of each metal solution were added to new centrifuge tubes and 15 M NH4OH was added until the solution changed color or a precipitate was formed.
Add 0.1M HCl one drop at a time. Use the stirring stick and stir each time a drop has been added. Determine the pH after 5 drops have been added. Repeat the procedure until 30 drops have been added. 4.
Materials and Methods Part 1 – Cation Tests Potassium, iron (III), zinc (II), copper (II), and cobalt (II) cation solutions were made subject to two elimination tests involving the addition of sodium hydroxide in one and ammonium hydroxide in the other. Approximately 10 drops of each cation solution were placed in 10 different centrifuge tubes. To begin the sodium hydroxide test, 6M NaOH solution was added to one sample of each cation solution until either a precipitate was formed or until 20 drops were added. An additional 10 drops of 6M NaOH was added to each solution in which a precipitate formed and the solutions were shaken lightly to aid in the mixing of the reaction. To begin the ammonium hydroxide test, 15M NH4OH was added to one sample of each cation solution until the formation of a precipitate was observed, with care not to exceed 20 drops.
Make sure to keep time, read the spectrometer, and record the data. Note time to the nearest second and mix the contents of tubes 2 and 3 by pouring them back and forth twice. Mixing should be completed within ten seconds. 5) Add the reaction mixture to a cuvette by pouring or using eye dropper, wipe the outside, and place the cuvette in the spectrometer. Read the absorbance at 20 second intervals from the start of the mixing.
9. Record observations for each hyphal tip in table such as the one below but do one for each hyphal tip and for two different slides. Calculate the speed of growth using s=distance/time. Table 2: Hyphal Tip with Growth Medium (Slide 1) Time(minutes) | Distance (um) | Speed (um/min) | | 1 | 2 | 3 | 1 | 2 | 3 | 5 min | | | | | | | 10 min | | | | | | | 15 min | | | | | | | 20 min | | | | | | | 10. To determine if hyphae grow at the same rate, graph the results of table 2 and compare the slopes of the 3 hyphae from the slide preparations.
Adequate separation will have occurred when the cresol red dye front has moved at least 50 mm from the wells. Gel may be stained either with 1 µg/ml ethidium bromide for 10 minutes or 0.05% methylene blue (or proprietary) stain for 30 minutes, followed by 20-30 minutes destaining with water. * If adding Bromophenol Blue loading dye to sample: do not add the loading dye to the entire sample, leave 10µl of sample without loading dye if you will be sending sample in for