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Unformatted text preview: Stephanie Verrell G.S.I. Tawnya Flick Section 820 Experiment 6: Determining Enthalpy of Magnesium Combusting Using Calorimetry Purpose: • By determining how much heat is given off when magnesium metal is burned we can verify that it is safe for Lonnie to burn magnesium metal in front of the lecture hall without the big shield. We were able to use Calorimetry and Hess’s Law to determine the change in enthalpy when magnesium metal combusts. Mg (s) + 2HCl (aq) → MgCl 2 (aq) + H 2 (g) MgO (s) + 2HCl (aq) → MgCl 2 (aq) + H 2 O (l) H 2 O (l) → H 2 (g) + ½ O 2 (g) Methods: You cannot go about measuring the enthalpy of the reaction directly because there is no way to measure it directly. It is hard to directly measure the enthalpy of this reaction because it is a solid reacting with a gas. Instead you can use calorimetry and Hess’s Law to find the change in enthalpy when magnesium metal combusts. Calorimetry is used to calculate the change in enthalpy of chemical or physical reactions. Hess’s Law is used to predict enthalpy change and conservation of energy. For the three enthalpies that used in this experiment to find the final enthalpy, two were determined in lab, and the other was determined from a reference book. The first step of the experiment is to calculate the heat capacity of the calorimeter. A known amount of room temperature water was added to the calorimeter and the initial temperature was recorded. At the same time the initial temperature of an ice bath was recorded as well. A known mass of the ice water was mixed with the room temperature water and the final temperature was recorded when the calorimeter reached an equilibrium and Kcal was calculated. The Kcal is important calorimeter reached an equilibrium and Kcal was calculated....
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- Spring '08