Experiment 22 Procedure Proposal Final (2)

Experiment 22 Procedure Proposal Final (2) - Dystan Medical...

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Unformatted text preview: Dystan Medical Supply Company: Cold Packs & Hot Packs A Self-Directed Experiment Meredith Frobose Duncan Wilder Meagan Rowe Pinal Patel October 18, 2010 Introduction Hot packs and Cold packs are great ways to relieve temporary pain for many people across the United States. These hot and cold packs contain two compartments in a plastic bag, one compartment contains salt and the other compartment contains water. When the bag is broken, the salt dissolves in the water, producing either an endothermic reaction or an exothermic reaction depending on the concentration of salt. An endothermic reaction will produce a cold pack as heat and energy are absorbed from the surroundings. An exothermic reaction will produce a hot pack as heat and energy are released to the surroundings (Stanton, Zhu, and Atwood 269). In this experiment we will be using four different kinds of salts. These salts include ammonium nitrate, calcium chloride, lithium chloride, and potassium chloride. All four of these salts will be tested to determine which should be used to produce efficient and economical cold and hot packs for the Dystan Medical Supply Company. Our research team must determine the mass of the salt to be used to produce a 100-mL cold pack that can attain a temperature of 0 degrees Celsius and a 100-mL hot pack that can attain a temperature of 65 degrees Celsius. By using the calorimeter to construct a thermogram, the salt reactions can be determined to be either endothermic or exothermic, which in the end will determine their relevant uses. In order to measure the heat of change in this reaction, we will use calorimetry. The first step in this process is to test a calorimeter and find out its calorimeter constant, or the amount of heat that the calorimeter absorbs from its environment. After calculating its calorimeter constant, the calorimeter cup is used to hold one reactant, and the initial temperature is measured. The additional reactant is then added to the calorimeter, and the MeasureNet system records any change in temperature that takes place during the reaction. Calculations that factor in the calorimeters calorimeter constant can be completed, which will tell how much heat a reaction emits or absorbs in joules. If the reaction has a positive change in heat, it absorbs heat and is thus an endothermic reaction. If it has a negative change in heat, it liberates heat and is exothermic (Whitten, Atwood, Morrison 551-552). Sample Calculations Part A: Calculate the Calorimeter Constant: The specific heat of water is 4.184 J/g C. The density is 1.00g/mL T= T f (equilibrium temperature of the system) T i m warm water = (mass of warm water)( Density of water) q calorimeter = - (m warm water x C warm water x T warm water ) (m cool water x C cool water x T cool water ) C calorimeter = q calorimeter T cool water Average calorimeter constant = C calorimeter trial 1 + C calorimeter trial 2 2 Parts B, C, D, and E: Calculate the H dissolution of the salts:...
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Experiment 22 Procedure Proposal Final (2) - Dystan Medical...

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