Pre-Lab Chem 151
Majed Al Dhwaihi
Chem 151 Lab
Prelab Assignment for week 3
Chemical Separation
Procedure:
Separating the sample:
First place a small amount of the spinach provided in the mortar, just enough to cover its bottom; combined with the sand provided to break down the call walls. A 1:1 mixture of hexane and acetone was determined to best solvent for this extraction. Knowing this add one mL of the pure hexane and one mL of the pure acetone to the mortar. Grind the contents until the cell walls have been adequately broken. Transfer the mixture to a centrifuge tube to separate the sample into layers, to help remove the water. Once the sample is finished spinning extract the organic layer and place in a test tube.
TLC: To determine which mixture acetone and hexane is the best developing solvent the first step is to make mixtures of these solvents in test tubes. In the first test tube mix one part acetone (.5 mL) and three parts hexane (1.5 mL), In the second test tube mix two parts acetone (1 mL) and two parts hexane (1mL), In the third test tube mix three parts acetone (1 mL) and one part hexane (.5 mL), in the last two test tubes use pure hexane in one (2 mL) and pure acetone (2mL) in the other. Place these test tubes in a test tube rack and set aside for later use. Get five TLC plates provided, do not touch the front of the plate keep it clean and dry. Make a pencil line on the plates far enough up so that it will be above the solvent when placed in the test tubes with the developing solvent. Use a capillary tube to draw up the spinach mixture and make small concentrated dots on the lines of the plates. Place the plates, spotted end down, in the test tubes and cover with the parafilm provided. Watch the developing when the developer is 1 cm from the top of the plate remove from the chamber and mark the line with pencil. Allow the plate to dry. View the plates under UV light marking the spots. Draw the results in the lab notebook and note the color of each
Chem 151 Lab
Prelab Assignment for week 3
Chemical Separation
Procedure:
Separating the sample:
First place a small amount of the spinach provided in the mortar, just enough to cover its bottom; combined with the sand provided to break down the call walls. A 1:1 mixture of hexane and acetone was determined to best solvent for this extraction. Knowing this add one mL of the pure hexane and one mL of the pure acetone to the mortar. Grind the contents until the cell walls have been adequately broken. Transfer the mixture to a centrifuge tube to separate the sample into layers, to help remove the water. Once the sample is finished spinning extract the organic layer and place in a test tube.
TLC: To determine which mixture acetone and hexane is the best developing solvent the first step is to make mixtures of these solvents in test tubes. In the first test tube mix one part acetone (.5 mL) and three parts hexane (1.5 mL), In the second test tube mix two parts acetone (1 mL) and two parts hexane (1mL), In the third test tube mix three parts acetone (1 mL) and one part hexane (.5 mL), in the last two test tubes use pure hexane in one (2 mL) and pure acetone (2mL) in the other. Place these test tubes in a test tube rack and set aside for later use. Get five TLC plates provided, do not touch the front of the plate keep it clean and dry. Make a pencil line on the plates far enough up so that it will be above the solvent when placed in the test tubes with the developing solvent. Use a capillary tube to draw up the spinach mixture and make small concentrated dots on the lines of the plates. Place the plates, spotted end down, in the test tubes and cover with the parafilm provided. Watch the developing when the developer is 1 cm from the top of the plate remove from the chamber and mark the line with pencil. Allow the plate to dry. View the plates under UV light marking the spots. Draw the results in the lab notebook and note the color of each