Isolation of Caffeine from Teabags by: Ma. Jessa Princess T. Romero John Jezreel Pardinas Submitted to: Mrs. Georgina Diopenes Abstract In this experiment, Caffeine was isolated from Tea, using hot water, sodium carbonate, dichloromethane, and was then purified using sublimation. The crude weight of caffeine was 0.048 grams. The experimental melting point in the 1st trial was 210 0C – 218 0C, in the 2nd trial was 212 0C – 220 0C. Introduction Caffeine is a molecule that is similar to the purine base xanthine.
Acid Base Titration Purpose: The purpose is to calculate the molarity of a NaOH solution by titrating the base with 5mL of standard HCl solution in each trial. By adding the base with unknown molarity to the acid with 0.10M the molarity of NaOH can be calculated. The base, NaOH, helps bring the pH of the acid, HCl, closer to seven, which neutralizes it. When using the buret the amount of NaOH used is able to be determined. Then by writing a balanced chemical equation and using the titration formula, Nb+Ma+Va=Na+MbVb , the molarity is able to be determined.
Once calculated, these results can be analyzed and will either validate or refute my hypothesis. Introduction (Library Research): Ascorbic acid (vitamin C) is found in orange juice. In this experiment, orange juice made from the concentrate was measured for decreases/increases of off-flavours (furfural and α-terpineol) and for decreases/increases of ascorbic acid. Sodium hydroxide (NaOH) as well as hydrochloric acid (HCl) were added during separate trials to change the PH in the orange juice. An increase of PH from 3.2 to 4.2 enabled the protection of ascorbic acid levels, without increasing the levels of other enzymes.
Experiment 1: Extraction of Caffeine from Tea The primary objective of the experiment is to separate the caffeine from tea leaves. The mixture of tea and the calcium carbonate is separated from tea leaves by vacuum filtration. The solvent used in extraction of caffeine is dichloromethane. Anhydrous magnesium sulfate is added to the dichloromethane solution to dehydrate the mixture. The dichloromethane is then separated from the mixture in the rotary evaporator.
At this point the volume of base used to neutralized the acid can be determined. Phenolphthalein is the indicator which is colorless in an acid but changes to a faint and permanent pink color in base. The purpose of this experiment is to prepare a sample for titration with a base, become familiar with a buret while using proper titration technique in reaching an end point. Hypothesis : If I titrate a base of known concentration with an acid of unknown concentration then I can determine the concentration can be calculated because of the titration calculation. Materials : • Vinegar • Two small beakers (150mL) • 250-mL Erlenmeyer flask • 10-mL graduated cylinder • 50-mL buret • Buret clamp • Small funnel • M NaOH Hazards : • Chemical spill • Broken glass
Titration lab report Chemistry unit 3 Abstract In this investigation it was looked at the titration of HCL with NaOH, this is a neutralization reaction that is performed in lab in order to determine an unknown concentration of acid (HCL). In this investigation the moles and concentration of acid as well as the Ph of the solution were find out, the mole of 25ml of HCL was 0.65, concentration was 0.026 and the Ph of solution was 1.58Ph. Introduction Titration is a process to measure the volume of an end product, which is produced by reacting a solution of known concentration with a measured volume of a solution of an unknown concentration. The known concentration solution is called a standard solution, it will be added from a buret to allow measure the amount of solution which is added. The solution that is added by buret also called titrant.
Determination of the pKa of Methyl Red by UV-Vis Spectroscopy February 16, 2010 (Partner:) ABSTRACT The purpose of this experiment was to obtain the pKa for an acid-base indicator. A spectrometer was used to determine the pKa of methyl red. The calibration curves were created by analyzing samples of known concentration at pH’s well above and below the pH indicator range for methyl red. Then samples of known pH were analyzed. By, solving the system of equations using linear algebra, the concentrations of the indicator and the conjugate base were determined.
Aim: | The aim of this experiment is to analyse a sample of vinegar and determine it’s concentration. | | | Hypothesis: | It’s expected that the aceatic acid will have the concentration of 0.1mol as this is the molarity of the NaOH as they have a 1:1 ratio of moles as it states in their chemical equations. | | | Apparatus: | * 1 x retort stand * 1 x retort burette clamp * 1 x burette * 1 x pipette * 1 x glass funnel * 2 x Conical Flasks * Sheet of filter paper * 200mL of 0.1 mol L-1 NaOH * 200mL of acetic acid of unknown concentration | | | Procedure: | 1. WARNING: Wear safety glasses and gloves! 2.
LIQUID-LIQUID EXTRACTION OF BENZOIC ACID J Wright Organic Chem Lab 1 Tuesday 1:40-5 Ian Stubbs LIQUID-LIQUID EXTRACTION OF BENZOIC ACID PURPOSE: The purpose of this experiment was to extract benzoic acid from an aqueous of benzoic acid using methylene chloride, use liquid-liquid extraction to calculate the distribution coefficient of benzoic acid and to determine whether a single extraction or multiple extractions are more efficient. Add in the table of physical constants. See the attachment for the lab format. PROCEDURE: Gather a two stock solution that includes; 0.02M of sodium hydroxide (NaOH) aqueous solution and 0.02M of benzoic acid aqueous solution. For a single extraction, use a 50mL graduated cylinder and measure out 50mL of the benzoic acid solution into a 125mL separatory funnel.
Tannins, which are organic compounds that can bind to alkaloids such as caffeine, are going to be taken out of the tea water using sodium carbonate. The sodium carbonate is a base, which will convert the acidic tannins into sodium salts that are highly soluble in water. Isolating the caffeine will continue once methylene chloride is added to the remaining tea solution, which increases the solubility of the caffeine. Methylene chloride can be evaporated quickly leaving the caffeine to be purified by sublimation. Materials and Methods: The tea solution was obtained when a tea bag was placed in boiling water and its liquid mix was carefully squeezed into a beaker; and eventually placed into a test tube.