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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 10.02 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 (CH2Cl2) by the same solid-liquid extraction technique used in Unit 1. After 25 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 919.4 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 10.02 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 (CH2Cl2) by the same solid-liquid extraction technique used in Unit 1. After 25 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 919.4 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?

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