Percentage Yield Lab Report

4- Set up reflux system using a clean and dry condenser . 5- Place the flask on the hot plate and heat the reaction for 45 minutes - 1 hour . 6- When the reflux is over , remove magnetic stirrer and allow the reaction to cool to room temperature . 7- Add 20 ml of ice water to a separating funnel

• Carefully decant the solvent solution from the drying agent through the funnel into the flask. Rinse the Erlenmeyer flask with about 10 ml of solvent and pour the solvent through the funnel, too. Remove the funnel, add two or three boiling chips and reattach the thermometer and adapter to the still pot. • Discard the magnesium sulfate remaining in the Erlenmeyer flask by dissolving it in tap water and pouring the solution down the drain. • Before beginning the distillation, weigh a clean, dry 1 narrow mouth screw cap bottle on a balance.

If any spattering occurs while heating, wash the solid back down into the solution using a wash bottle. Heat the solution until all the blue solid has been decomposed to the dark colored copper(II) oxide. Allow the mixture to cool before filtering. Fold a piece of the Whatman filter paper while waiting for the mixture to cool. To fold the Whatman paper, you first fold it in half, and then in half again.

Swirl the solution to ensure that the oxalic acid crystals are properly dissolved in the deionised water. C) Measuring pH of HCl Solution (unknown Concentration) with an indicator 1. Pour 20 ml of HCl into a

We added sodium carbonate until the pH of the mixture was 8. After neutralize, we collected benzocaine by vacuum filtration. We used a Buchner funnel to collect benzocaine. We used three 10 ml of water to wash the product. After the product was dry, we weighed, calculate the percent yield and determined the melting point of the product.

The crude tetraphenylnaphthalene in a 25-ml Erlenmeyer flask and dissolved in boiling isopropyl alcohol (12 ml). The solution was cooled to room temperature and further cooled in an ice bath for 30 minutes. Crystallization of colorless crystals occurred. The product was collect in a Hirsch funnel and washed with isopropyl alcohol. The solid was left to dry over the weekend.

Making tea solution: Take around 3 gram of tea from tea bags and record the weight with an uncertainty of ± 0.001 using an high accuracy balance. Take 400 ml beaker add 200 ml of distilled water to it. Start heating it up with the bunsen burner until 150ml remain. (recommended ratio of 1 g of tea : 50ml of water) Measure the temperature of water and wait till it reach the expected value Add the tea leaf once the water is 150ml(some will evaporate during the heating) and keep the temperature at a constant degrees by using a water bath. Using a stopwatch to determine the amount of heating time.

Mixing .20 milligrams of the commercial dye (red dye #3) with 250 ml of distilled water to get the initial concentration, the goal is basically to get the absorbency level below 1. Putting the dye solution in the blank cuvette and observe the absorbance level that it dorms. Repeat the steps five times making different dilutions to maintain multiple absorbance values. The second week was making another commercial dye solution and also testing the food dye brought into class. Calibrate the spectrophotometer the same exact way so that it does not mess up the calculations gathered.

Ensure that solid is completely dissolved using a stirring rod. Next, a 10 mL beaker is filled with 3 mL of HCl and measure 10 mL of ionized water into a 140 mL beaker. Carefully turn on laboratory burner and start cleaning the Nichrome wire by dipping it into concentrated HCl acid. Hold the Nichrome wire on top of the flame and repeat the step until the wire doesn 't show any color. When the wire is clean, dip the wire again with some of the acid and dip it into the solution with the unknown compound in it.

In 10 g dried sediment sample added 7 ml 0.2 M NH4Cl solution. A mixture of 100 ml hexane: acetone (1:1) was used as a solvent to extract pesticides with overnight shaking for 12 h on reciprocal or wrist action shaker at 180 rpm. The extract was carefully decanted through activated florisil column (2-3 cm), giving twice wash with25 ml hexane: acetone (1:1) to the sediments. The elute was then washed with 200 ml water and then again aqueous layer was extracted with 50 ml hexane. Finally the hexane layer was washed with 100 ml water and then evaporated to dryness with a vacuum rotary evaporator.