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Calorimeter lab. What is the change in enthalpy for magnesium after the reaction with vinegar?

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Introduction: The first law of thermodynamics states the total energy of an isolated system cannot be created or destroyed. Since chemical energy is the sum of heat plus work many chemical reactions involve the evolution of heat or production of work. An example is a car engine that converts the chemical energy stored in gasoline into heat and work. This heat that is exchanged can be measured with an apparatus called calorimeter. A calorimeter is an insulated vessel preventing the heat from escaping into the surrounding. The thermometer is used to measure the temperature change and the stirrer is used to ensure the heat is uniformly distributed. ...read more.


The apparatus was moved to the front of the class where the teacher set up the thermometer attached to the laptop showing the temperature. A Styrofoam cup with two holes for the thermometer and another for the stirring rod was set up and was placed on top of the apparatus as tightly as possible so not a lot of the gas can escape. The initial temperature was measured using the thermometer. The top was removed, the magnesium was added and quickly the top was placed back on to the top. The stirring rod was used to mix the solution inside the calorimeter. The thermometer connected to the computer showed the temperature increase and decrease as a graph. ...read more.


mol ΔH = -Q ÷ nmg = -2366.4704 J ÷ 0.0082 mol = -288.59 kJ/mol The change of enthalpy is -288.59 kJ/mol for the magnesium. Conclusion The hypothesis was right because the change of enthalpy of the magnesium is -288.59 kJ/mol. A lot of heat is released from this reaction. 0.2 g of magnesium was used with 20.0 mL of vinegar. The initial temperature of the calorimeter was 24.7 °C and the finial being 52.7 °C. The magnesium reacts with vinegar (CH3COOH) because of the oxygen present. The reactivity of the magnesium increase as the oxygen level increases. This single displacement reaction of the magnesium and the vinegar reacts and forms hydrogen gas. Reference: Biology 12. Toronto: McGraw-Hill Ryerson, 2011. Print. ...read more.

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