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Unformatted text preview: Rachel Golub 11-01-06 CHM 102 Lab Report Experiment 7: Measuring Heat Transfer with a Calorimeter INTRODUCTION: In this experiment, I will be measuring heat transfer with a calorimeter using exothermic and endothermic reactions. An exothermic reaction is a chemical reaction that generates heat, meaning heat is going out. An endothermic reaction is a chemical reaction that absorbs heat from its surroundings, meaning heat goes in. Combustion reactions are strongly exothermic, while endothermic reactions are far less common. EXPERIMENTAL PROCEDURE: To start the experiment, a 250 mL beaker was filled full with water and placed on a hot plate to be heated. A metal cylinder was obtained and weighed, the mass being recorded in my data table. Using a pair of metal tongs, the metal cylinder was lowered into the beaker of water. A calorimeter was obtained, in this case a plastic thermos, and was weighed. The calorimeter was then filled half-full with cold water and weighed again. Both weights were recorded in my data table. The temperature of the water was recorded as my initial temperature. The temperature of the water in the beaker was also recorded as the initial temperature of the metal. The metal cylinder was quickly transferred to the calorimeter containing the cold water. After the temperature was monitored for a few minutes, it was recorded as the final equilibrium temperature for both the metal and the water. The procedure was repeated once more. For part II, a calorimeter was assembled using a sauce sup and a cover. The empty calorimeter was weighed and the mass was recorded in my data table. 15 mL of water was added to the calorimeter, which was then reweighed, the mass being recorded in my data table. A thermometer was inserted through the cover of the calorimeter. When the temperature of the water became constant, it was recorded as the initial temperature. 5 different salts were used in this experiment. 1.0g of one of the salts was weighed. The name and formula of the salt, as well as the mass, was recorded in my data table. The salt was carefully added to the calorimeter. The temperature was carefully monitored until it reached a minimum or maximum temperature. This temperature was recorded as the final equilibrium temperature. This procedure was repeated 4 more times, each with a different salt. For part III, the same calorimeter used in part III was weighed and the mass was recorded. 15 mL of hydrochloric acid was added to the calorimeter, which was recorded....
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- Fall '06