Pour all the filtrate and washings into a 250cm3 volumetric flask. Make up to 250cm3 with 1.0mol dm-3 sulphuric acid(VI) acid. Stopper the flask and invert several times to thoroughly mix the solution. 5. Fill the burette with 0.005mol dm-3 potassium manganate(VII) solution.
Example: Cup 2 is made up of half stock solution and half tap water, which is a 50 percent relative salt concentration. m. What are the absolute salt concentrations of cups 1–4? (If you want to convert to metric units, 1 cup of salt is about 292 g, and 1 qt. of water is 0.946 liters [L].) Write these concentrations down in your lab notebook.
The absorption spectrum is measured using a spectrophotometer and the data is graphed in Excel. The peak of the line is used to find Vmax of Fe2+. Vmax is used to find the moles of Fe2+ and ligand. The unknown n is a ratio of moles ligand divided by moles Fe2+. Results and Discussion For the first part of the experiment (Part A), five different 100 mL volumetric flasks were each filled with 1,2,3,4 and 5 mL of iron (II) solution.
-Use the titrations of the following chemical reactions: NaHCO3 + HCl (aq) NaCl (aq) + H2O (l) + CO2 (g) 2HCl (aq) + Na2CO3 (s) 2NaCl (aq) + H2O (l) + CO2 (g) Experimental procedure- Two Erlenmeyer flask must be labeled “unknown 1 and unknown 2”. Assure that all containers used are dried and cleaned properly. Two bigger flask are labeled “waste” according to each unknown. A pipette is set up and primed with HCl. The two unknown solids are weighed to a mass of 0.15g each.
0.9 0.8 0.7 Absorbance 0.6 0.5 0.4 0.3 0.2 0.1 0 400 450 500 550 600 650 700 750 λ max 500 nm 550 nm • • Make sure you understand the directions for using the spectrophotometer and have them written in your manual. Complete the questions on the prelab page. Introduction: There are many different chemical methods that can be used to determine the concentration of a solution. You have already used one method, titration, to find the concentration of Ca+2 ions in a sample of water, and another, density, in finding the concentration of ethanol. In this lab you will use a method called visible spectroscopy to determine the concentration of a solution of CoCl2.
c. Prepare the solution by dissolving 38.90 grams of ZnI2 with 500 mL of water. d. 0.0125/0.25 = 0.05 L = 50 mL. This produces 0.0125 moles of ZnI2 5. Exercise 5: a. (0.125)(0.1) = 0.0125 moles of solute b. Pour 50 mL of the stock solution to get the number of moles needed.
Pour the contents of one of the test tubes into the other and a reaction should occur and you should see a white precipitate of barium sulfate form. Then, centrifuge it for 1 minute. On the side, weight a boiling test tube containing 2 boiling chips. When the separation is complete, remove the small test tubes from the centrifuge and decant the supernatant into the boiling test tube. Add 1 mL of deionized water to the small test tube containing the precipitate and mix it and centrifuge it for 60 seconds.
The R tube will then be put in a large beaker. Another large test tube, boiling tube will be needed, along with a Pasteur pipet. A regular sized test tube will be labeled “C” for “colored solution,” and the new boiling tube will be labeled “P” for “product”. One boiling chip will then be placed into the P tube. 5mL of acidified water will be measured, using a graduated cylinder, and will be transferred to the R tube, and will be immediately vigrously mixed with the reactants.
Lastly add 1 mL of water using the buret for water to the last beaker, and label this beaker “Green”. Clean and dry 4 cuvettes. The next part of the experiment is to actually use the spectrophotometer to find the absorbance of the green, yellow, and blue tubes. First, make sure the spectrophotometer is connected to the computer. The first step is to calibrate the blank or the background, and to do this, a cuvette of distilled water is inserted into the spectrophotometer.
Next, 50 mL of distilled was placed into the 150 mL. Twenty drops of Bromothymol blue were added to the 150 mL beaker solution. The pH was then recorded. Five mL of this solution was transferred into three separate 100 mL beakers. In one of these beakers, 1 mL of HCl was added to the solution, making this the “Yellow” beaker.