How to Test the Combustion Value of Oil

The combustion value of any material is the amount of energy it produces when fully burned. In scientific terms, it is when one mole of a substance undergoes full combustion in the presence of oxygen at a constant pressure. All substances have different combustion values, with some creating more heat than others. For example, most oils tend to burn with more energy. The different types of oil also produce varied combustion values, which is why some oils are better for certain tasks.

Things You'll Need

  • Chemistry tripod
  • Heat mat
  • Glass beaker
  • Spirit burner
  • Clip on thermometer
  • Water
  • Oil
Show More

Instructions

  1. Experiment

    • 1

      Fill the glass beaker with 250 grams of water and clip the thermometer to the side of the beaker, leaving its base sitting in the center of the water. Do not let the thermometer bulb touch the bottom, as this will adversely affect the reading.

    • 2

      Set up the tripod with a heat mat so it can hold the beaker securely when it is placed on top of the setup. Make sure the beaker can sit on the tripod and not fall over before beginning the experiment.

    • 3

      Add 35 grams of the test oil to the spirit burner and position it below the beaker. Use a long match to light the wick on the spirit burner to start the experiment.

    • 4

      Record the water temperature before the spirit burner is lit. After the water temperature has risen by 15 to 20 degrees, blow out the spirit burner and record the new temperature.

    • 5

      Allow the spirit burner to cool before weighing how much of the oil is leftover after the burn.

    Solving the Equations

    • 6

      Divide the mass of oil used by the experiment by the known molecular mass for the oil itself (every substance has a unique molecular mass). This equation indicates how many moles of the oil were burned.

    • 7

      Multiply the specific heat capacity of water, which is 4.184 Jkg, by the mass of the water and the temperature change of the water recorded in the experiment. This equation indicates the energy required to change the water temperature.

    • 8

      Divide the energy required to change the water temperature by the number of moles of oil burned. This equation produces the combustion value for the oil, which is measured in kilo-joules per mole.

Learnify Hub © www.0685.com All Rights Reserved