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creating a virtual lab




Virtual Lab Experiment;Chocolate is a popular snack throughout South America, North America and Europe. In addition;to its high energy content (33% fat and 47% sugar) chocolate packs an extra punch with the;stimulant caffeine and its biochemical precursor theobromine. Theobromine comes from the;Greek word meaning food of the gods and it is a diuretic, smooth muscle relaxant, cardiac;stimulant, and vasodilator. Caffeine is a central nervous system stimulant.;Too much caffeine is harmful for many people, and in a small fraction of the population even;small amounts of caffeine cannot be tolerated. How much caffeine is in a chocolate anyway?;And how does that amount of caffeine compare with the amount of caffeine found in a cup of;regular coffee?;For this thought experiment you will design an analytical chemistry method using equipment and;reagents selected from a master list (see below). The goal is to determine the amount of;caffeine in a regular size chocolate bar and an 8 oz. cup of coffee. The second goal is to;determine if coffee and chocolate have the same amount of caffeine per serving or not. You;need to describe in detail the following;1. A hypothesis;2. A very detailed step-by-step experimental protocol that includes chemical standards and;calibration curves to measure the amount of caffeine & theobromine in the samples. The;experiment is designed using some (not all!) reagents and equipment provided in the;master list below.;3. Two fictitious data sets (one for a chocolate bar and one for coffee) which you decide will;either support or refute your hypothesis;4. Statistical analysis of the fictitious data;5. A clear, balanced conclusion;Master List of reagents and equipment;Lab notebook, pen (not pencil!) and scotch tape;Computer running Windows 7 with Microsoft Excel 2010 and Microsoft Word 2010;1 regular sized dark chocolate bar;1 8 oz. cup of regular brew coffee;Ceramic mortar and pestle;Blender;Fridge;Freezer;Electronic analytical balance capable of measuring mass down to 0.10 mg;5, 10, 25, 50 and 100 mL burets;1,2,5,10,25,50,100,200,250,500,1000, & 2000 mL volumetric flasks;0.2-2, 1-10, 2.5-25, 10-100, & 100-1000 uL adjustable micropipette with matching disposable;tips;1,10,50,100 & 500 uL Hamilton syringes;Fritted-glass funnel with electronic air pump;Conical funnel and filter paper;Syringes and 0.45 micrometer filter;50, 100, 500 & 1000 mL beakers;50,100,500, & 1000 mL Erlenmeyer flasks;Vacuum desiccator;A copious supply of tap water;A copious supply of double distilled water;Hot plate;Pure standard of 50% caffeine (w/v) in water;Pure standard of 50% theobromine (w/v) in water;500 mL container of petroleum ether;Centrifuge with disposable centrifuge tubes;Chromatography pump with UV detector;SiO2 solid phase matrix column;C18 solid phase matrix column;Sephadex G-10 size exclusion column, Sephadex G-25 size exclusion column, Sephadex G-50;size exclusion column, Sephadex G-100 size exclusion column;chromatography column packed with anti-caffeine antibody coated beads;acidic solvent (79 ml water: 20 ml methanol: 1 ml acetic acid);basic solvent (79 ml water:20 ml methanol: 1 ml NaOH);phosphate buffered saline, pH = 7.4;Of course you may use the internet and primary literature to help you design your scientific;protocol. Your major challenge is taking the time and mental effort to address every aspect of;the experiment that you can try to anticipate potential challenges, inefficiencies, sample loss;and loss of analyte. The more detailed and comprehensive you are in your description the;better.;Dont underestimate the fictitious data set you are going to generate for this project. Based on;your internet research you need to make the data realistic. Once you have the data you are;going to need to use Excel to do statistical analysis. You will also need to be cognizant of the;number of significant digits. Dont forget to show standard deviations for your mean values and;explain to me the rationale you used to decide which statistical method was best for comparing;the chocolate vs. the coffee data.;This project is due no later than the last day of class.;Feel free to contact me at if you have questions. My cell phone is 858245-7158


Paper#15751 | Written in 18-Jul-2015

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