Measuring the Enthalpy change of combustion
This simple experiment is carried out to show the difference in the enthalpy change of combustion between two fuels, hexane and methanol. These fuels are individually weighed before and after used as heat source to heat water in a calorimeter. The result is used to find out amount of heat transferred by the fuel, amount of fuel used and the enthalpy change of combustion. Introduction
Enthalpy change of combustion is the enthalpy change when a substance completely reacts with oxygen under standard conditions. This experiment is carried out to show how this enthalpy change of combustion is different in different fuels. For this experiment I took two fuels methanol and hexane. The experiment doesn’t require much special equipment except for the weighing machine. The experiment was carried out in room . Methods and equipments
Small copper can or a metal container
Spirit burner containing hexane
Spirit burner containing methanol
Put 200 cm3 of water is placed in a calorimeter or a beaker. Position a thermometer bulb near the middle of the volume of water and record the result as initial temperature. Adjust the calorimeter with a clamp on a balance and leave enough space below the calorimeter for the burner. Add some sort of draught shield or any cardboard, books to avoid energy loss. This is important as continuous loss of heat can have significant change in the result. Weigh the spirit burner for both the hexane and methanol before lighting them. Place one of the spirit burner under the calorimeter supported on a stand. Remove the burner’s cap and light the wick. Make sure the flame is not to low or too high. Stir the water with thermometer at all times until the temperature reaches 15-20 C. Make sure excessive heat is not lost during the heating by introducing draught exclusion system. Extinguish the burner by covering it with...
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