16 Nov 2015

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Calculating Your Jitters

Date Performed: 09/15/2015 Alexander Wilsey

Date Submitted: 09/22/2015

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Lab 03 - Calculating Your Jitters: The Mass Percent of Caffeine in Coffee: Calculating Your Jitters

Wilsey, Alexander

Abstract

Caffeine is a stimulant, also considered a drug, that affects a person's central nervous system. However,

many people tend to ignore the fact that they consume this drug on a regular basis. Whether it be in their

morning cup of coffee or in their favorite soda, caffeine can be very dangerous if excessive consumption

occurs.

Since caffeine is one of the main components of coffee, the mass percent is calculated to see what

percent of coffee is made up of caffeine. The way that the mass percent of a substance is calculated is to

take the mass of the total solution and divide that by the mass of the isolated solution. But in order to get

the mass percent, the mass of the caffeine must be found. This is done by finding the LD50.

The purpose of this experiment is to calculate the amount of coffee needed to be in jeopardy of getting

the "caffeine jitters." To get the jitters, one would need to consume approximately 20% of the LD50 of

caffeine, or the lethal dosage for 50% of the population. In order to calculate the lethal dosage, the

formula used is 150mg of caffeine per kg of body weight. In the experiment, if caffeine is extracted from

30.0mL of coffee and the LD50 is calculated, then it will require approximately 5 cups of coffee to get

the jitters, and 25 cups to reach the lethal dosage.

This hypothesis was tested by putting 30.0mL of coffee and around .600g of Sodium Carbonate in a

separatory funnel. Along with the mixture, Dichloromethane was added to help separate the caffeine

from the coffee. Once mixed and settled, the clear liquid was drained from the funnel into a beaker. That

beaker was then put on a hot plate to evaporate all of the leftover solution so that only the pure caffeine.

The caffeine was weighed and was used to find the mass percent by dividing the mass of the total

solution by the mass of the caffeine times 100 percent.

The LD50 was calculated by dividing 150mL caffeine by body mass in kg. This gave the amount of

caffeine in milligrams. The amount was converted into grams and then multiplied by 30 mL and then

decided by the mass of the caffeine calculated before. This gave us the amount of mL of caffeine that it

would take to kill half of the people in the population.

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Lab 03 - Calculating Your Jitters: The Mass Percent of Caffeine in Coffee: Calculating Your Jitters

Wilsey, Alexander

Procedure

Lab 3 Calculating Your Jitters: The Mass Percent of Caffeine in Coffee. General Chemistry 1 Lab

Manual. Bluedoor Publishing, LLC. 2015. 9/15/2015. https://www.bluedoorlabs.com/online_manual.

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