Chemistry Lab-Report
Planning A
1) Aim: To determine the enthalpy changes for three alcoholic fuels.
2) Background knowledge: Heat of combustion of a substance is defined as the amount of the heat liberated when one gram mole of the substance is completely burnt. It is measured in kilo calories. A known quantity of alcohol is made to burn and the heat liberated is used in raising the temperature of water the amount of heat liberated can be calculated, from which the heat of combustion of alcohol is calculated.
3) Hypothesis:
4) Variables:
Planning B
5) Spirit lamps (with each of the fuels separately), copper Calorimeter with stirrer, retort stand with clamps, tripod stand, thermometer, windshield, measuring cylinder (100 ml)
6) +7)
- Weigh the spirit lamp, containing the given amount of the alcoholic fuel accurately (including the flame cap).
- Using a measuring cylinder, pour 100 ml. of water in the Calorimeter.
- Keep the Calorimeter on a tripod stand, suspend the thermometer in water and record the initial temperature of water.
- Keep the spirit lamp below the calorimeter and adjust the height of the spirit lamp so that the flame of the spirit lamp should touch the bottom of the calorimeter.
- Light the spirited lamp and cover the lamp with the windshield so that the flame may not flicker.
- Stir the water continuously and observe the rise in temperature.
- When the temperature rises by about 20ºC extinguish the flame at once by putting the flame cap, and simultaneously note the exact temperature of the water.
- Cool the spirit lamp and weigh it accurately with the remaining unused alcohol fuel.
