Care must be taken when squeezing the pipet bulb on the filter pipet. Too much pressure might cause the filter to leak or fall off. Add about 2 mL of fresh tert-butyl methyl ether to the solid in the RB flask, warm briefly, let the solids settle for a minute, and pipet the liquid to the centrifuge tube as before. Again allow the solids to settle briefly in the centrifuge tube, then filter the liquid through the pressure filtration apparatus, into the same 25 mL Erlenmeyer flask. Doing a rinse such as this helps to ensure that any trimyristin that was left behind in the RB flask and centrifuge tube is not lost, thereby helping to ensure that
After that, dissolve the sample in 2 mL of deionized water and shake the test tube for 1 to 1 ½ minutes to dissolve the solid. Place another dry test tube in a 50mL beaker and weigh it. Find a bottle of barium iodide and record the name and molar mass. Then, weight out either anhydrous barium iodide or barium iodide dehydrate into this test tube and dissolve is it in 2 mL of deionized water. 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.
Using a test tube holder, heat the R tube over the Bunsen burner, moving the tube in a circular motion until all the water has evaporated. The P tube will be carefully heated next, for about 10 minutes, until all the water has evaporated, and there is a white substance in the tube. After the water has evaporated, continue heating the tube over the burner for a minute longer, being careful to watch out for purple gas and yellow spots. The P tube
Obtain an Erlenmeyer flask that has a vacuum opening and attach the vacuum tube to it 8. Insert funnel and rinse the funnel with distilled water 9. Turn vacuum on and pour the pink solution into the Erlenmeyer flask, the precipitate should stay on top of the filter 10. Rinse the beaker out until all residue is gone 11. Try to rinse the precipitate in the funnel until the pink color is gone 12.
Obtain a clean-dry test tube. Place 0.3g of the unknown substance in the test tube. Next, add 10mL of distilled water to the test tube. Mix with a stirring rod until unknown is dissolved. 2.
After all the acid has been completely added and the reaction has stopped, use a pipette to add a few extra drops of acid into the beaker until the reaction stops. 7. Place the beaker on a hot plate and heat on a high setting to boil off the water. WARNING: THERE WILL BE A SMALL AMOUNT OF HYDROCHLORIC ACID BOILING OF THE MIXTURE. DO NOT PLACE YOUR FACE DIRECTLY ABOVE THE BEAKER.
The aspirator was turned to medium high, and then the copper was poured onto wetted filter paper. Using distilled water to remove all copper from the beaker. Once completely on filter paper 6mL of acetone was added to the copper to help dry it out. The filter paper was then removed and set down to dry completely. Once dry the filter paper was weighed with the copper on it and subtracted from the original weight to see the amount of copper left after
Using a measuring cylinder, add 50cm3 of 1.0mol dm-3 sulphuric(VI) acid to the thyme extract in the conical flask. 8. Titrate the solution in the conical flask with the potassium manganate(VII) solution until a pale pink colour persists for 10 seconds. 9. Repeat the titration until there are two titres within 0.1cm3 of each other.
While stirring, 6 M NaOH was added drop-wise until the solution became basic, turning red litmus paper blue. A total of 3.84 mL NaOH was required to achieve this; the resulting solution appearing dark blue with cloudy precipitates. The solution was then heated gently atop a hot plate to catalyze the next reaction, with care taken to assure all residue was kept off the walls of the beaker. Heating continued until the reaction reached completion and the solution slowly changed from blue to a dark green and finally black. At this point the heat was turned off to allow the black solid in the beaker, CuO, to settle to the bottom.
Then proceed to decolorize with 95% ethanol until the ethanol running off the slide is clear. Briefly rinse with distilled water. Counter-stain with safranin (secondary stain) for 1 minute then rinse with distilled water and gently blot dry with a paper towel. Lastly observe slide using oil immersion with the 100x