Caffeine occurs naturally in tea leaves and coffee beans. Pure caffeine (mp 236°C) is a white crystalline solid material at room temperature. It is classified as an alkaloid - a nitrogen-containing basic compound that is obtained from plants and has physiological effects in the body. A student pulverizes 8.78 grams (g) of coffee beans into a finely ground powder by using a mortar and pestle. The caffeine is then extracted into 300 mL of boiling dichloromethane (CH2CII2) by the same solid- liquid extraction technique used in Unit 1. After 30 minutes, the solution is filtered hot to remove a large amount of brown insoluble material. Dichloromethane is removed from the filtrate via rotary evaporation, leaving 916.3 milligrams (mg) of caffeine behind, as a white solid. What is the percentage of isolated caffeine with respect to the starting amount of crude coffee beans?

Caffeine occurs naturally in tea leaves and coffee beans. Pure caffeine (mp 236°C) is a white crystalline solid material at room temperature. It is classified as an alkaloid - a nitrogen-containing basic compound that is obtained from plants and has physiological effects in the body. A student pulverizes 8.78 grams (g) of coffee beans into a finely ground powder by using a mortar and pestle. The caffeine is then extracted into 300 mL of boiling dichloromethane (CH2CII2) by the same solid- liquid extraction technique used in Unit 1. After 30 minutes, the solution is filtered hot to remove a large amount of brown insoluble material. Dichloromethane is removed from the filtrate via rotary evaporation, leaving 916.3 milligrams (mg) of caffeine behind, as a white solid. What is the percentage of isolated caffeine with respect to the starting amount of crude coffee beans?

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

See similar textbooks

Similar questions

The amount of tartaric acid is responsible for the tartness of wine and controls the acidity of the wine. Tartaric acid also plays a very significant role in the overall taste, feel and color of a wine. Tartaric acid is a diprotic organic acid The chemical formula for tartaric acid is C4H6O6 and its structural formula is HO2CCH(OH)CH(OH)CO2H. A 50.00 mL sample of a white dinner wine required 21.48 mL of 0.03776 M NaOH to achieve a faint pink color. Express the acidity of the wine in terms of grams of tartaric acid, H2C4H4O6 (M. M. = 150.10) per 100 mL of wine. Assume that the two acidic hydrogens are titrated at the end point. MM H2C4H4O6 = 150.10 MM NaOH = 40.00 Below is the balanced chemical equation for this titration.
Phenylamine is an aromatic amine that is used in the manufacture of dyes. When absorbed through the skin itcauses the Fe+2 in hemoglobin to become oxidized into Fe+3, resulting in the formation of methemoglobin whichcannot bind to or transport oxygen. Phenylamine is soluble in water and acts as a weak base.C6H5NH2 (aq) + H2O (ℓ) ⇋ C6H5NH3+ (aq) + OH- (aq)a. When you measure the concentrations of the ionized substances you find them to be:[C6H5NH2] = 0.234 mol/L [C6H5NH3+] = 2.8 x 10-5 mol/L [OH-]= 2.8 x 10-5 mol/LIf the Kb is 4.27 x 10-10, is the reaction at equilibrium? If not, which direction does it need to move (rightor left) to reach equilibrium? Explain. b. At equilibrium the concentrations of the ionized substances are:[C6H5NH2] = 0.0537 mol/L [C6H5NH3+] = 4.79 x 10-6 mol/L [OH-]= 4.79 x 10-6 mol/LIf this reaction is taking place in a 2.0L container, and 1.5 moles of phenylamine were added to thereaction, what will the new concentrations of the three ionic species be when…
Jojoba oil is the liquid produced in the seed of the Simmondsia Chinensis (jojoba) plant, a shrub, which is native to southern Arizona. The main component is gondoic acid and the structure is shown below: From the structure of gondoic acid, what properties do you think it gives the hand cream? Explain.
Alkaloids are basic nitrogen-containing compounds of plant origin, many of which are physiologically active when administered to humans. Ingestion of coniine, isolated from water hemlock, can cause weakness, labored respiration, paralysis, and eventually death. Coniine is the toxic substance in the “poison hemlock” used in the death of Socrates. In small doses, nicotine is an addictive stimulant. In larger doses, it causes depression, nausea, and vomiting. In still larger doses, it is a deadly poison. Solutions of nicotine in water are used as insecticides. Cocaine is a central nervous system stimulant obtained from the leaves of the coca plant.Classify each amino group in these alkaloids according to type (primary, secondary, tertiary, aliphatic, aromatic, heterocyclic).
Cream of tartar is a white powder sometimes used in baking. (It's what separates a tangy, chewy snickerdoodle from an ordinary cinnamon-coated sugar cookie. The acid in the cream of tartar gives snickerdoodles their distinctive tangy flavor, and the chew happens because cream of tartar prevents sugar in the cookie dough from crystalizing into crunchiness. Allrecipies.com) Cream of tartar (KHC4H4O6) is the conjugate base salt of tartaric acid (shown to the right). The Ka for another similar acid is 8.7×10-3. What is the standard Gibb's free energy (in kJ/mol) for the dissociation of that other acid?
A student weighs out exactly 1.562 grams of p-aminophenol and exactly 40 mL of water. After dissolving p-aminophenol in HCl, 10 mL of acetic anhydride is added. The student follows the procedure and acetaminophen is prepared. What is the maximum amount of acetaminophen she could obtain from the reaction if the percentage yield is 76%?
which are the main ingredients in certain pesticides and “nerve gases”
What is the purpose of the concentrated sulfuric acid in the preparation of aspirin?
17. Is caffeine an addictive substance? If so, is it psychologically addictive, physiologically addictive, or both? What about chocolate? Bubble gum? How are such distinctions made? A common scene in movies and TV programs shows the detective tasting a suspected drug powder to determine its identity. In addition to being poor laboratory practice, it is a really bad idea. Discuss and explain. 18.
7b. Please help
Polyphenols are compounds found in many fruits, vegetables, tea, and wine. Predict the solubility of this polyphenol, gallic acid, in water.
Which of the following compounds is insoluble in water? (NH4)2S CaCO3 NaOH Ag2SO4 Pb(CH3COO)2