Hot and Cold Packs

# Hot and Cold Packs - Hot and Cold Packs By Lionel Sims III...

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Hot and Cold Packs By Lionel Sims III Lab Instructor: Anund February 15, 2008

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Results and Discussion: This lab was broken into two different weeks in order to fit in all the different procedures and calculations. The ultimate purpose of this experiment was to find what composition of materials, and chemical reactions would produce a working hot or cold pack that would successfully and repeatedly produce a 3º C change from its original temperature. Week 1 : A rudimentary calorimeter was devised out of Styrofoam cups, distilled water, and a thermometer. The intention was to quantify the exact amount of heat given off or absorbed by a specific chemical reaction. First the Heat Capacity (C) of the calorimeter had to be calculated as to not allow for any heat it absorbed to contaminate our results. The equation that would be used to find the heat capacity was derived thusly: q Calorimeter + q Cold Water + q Hot Water = 0 q Water = (msΔT) C Calorimeter = - 29 ∆Τ - r Calorimete HotWater ColdWater T T ms ms ) ( ( Because q is a value of energy it is measured in Joules, and because Temperature is measured in degrees Celsius, we know that the unit for the heat capacity of the calorimeter was going to be J/ºC. The value s is a constant which means the specific heat of water which is always 4.184. First, two Styrofoam cups were taken and one had its rim removed so that it would fit snugly inside the other and then the long probe of the thermometer was placed so that it punctured the bottom of the cup upside down on top and reached near the bottom of the entire system but not touching the interior base of the second cup. The next step was to establish q values of hot and cold water. A mass of distilled water was obtained and placed in the calorimeter and it was closed immediately. The temperatures were watched and recorded until they appeared to stabilize. The mass and the change in temperature were then recorded. Then another mass of distilled water was obtained and this time it was heated a few degrees and then
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Hot and Cold Packs - Hot and Cold Packs By Lionel Sims III...

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