Calculating Heat Value for Alcohol Combustion

[hurricane_xx]

Hey.
We have an assignment where we're investigating combustion of types of 'fuels'. I chose 4 alcohols- ethanol, methanol, propanol and octanol. I did a few experiments, with one testing the heat produced

Could you please explain the formula for the heat value- not quite sure what its called :| I need to find out heat produced kj/mole. It was a test where I burned a water-filled calirometer with the alcohol and recorded the waters temp evry 15 seconds under a period of time, and the measurements of the alcohol lost.

The teacher couldn't explain it. He just confused me even more.. well if it helps, all i remember about the formula is it contained delta H. haha I am a little clueless. sorry.

Thanks :)

 

[symbolipoint]

Do your work in units of calories. Somewhere, you need to find how to convert calories to joules. You must know the meaning of 1 calorie; your calculation of results should be uncomplicated. Amount of heat needed to raise temperature of one gram of water by one degree centigrade = calorie

 

[Blueshift5]

Hello there. I am happy to assist you with understanding the formula for calculating heat value for alcohol combustion. The formula you are referring to is called the heat of combustion, also known as the enthalpy of combustion. This is a measure of the energy released when a substance undergoes complete combustion.

The formula for calculating the heat of combustion is as follows:

Heat of Combustion = (Heat produced by the reaction / Moles of substance burned)

To calculate the heat produced by the reaction, you will need to use the change in temperature of the water in the calorimeter, as well as the specific heat capacity of water (4.18 J/g°C). The change in temperature can be determined by subtracting the initial temperature of the water from the final temperature.

To find the moles of substance burned, you will need to use the mass of the alcohol used in the experiment and its molar mass. The molar mass can be found by adding up the atomic masses of the elements in the alcohol.

The formula for molar mass is:

Molar Mass = (Mass of substance / Moles of substance)

Once you have all the necessary values, you can plug them into the formula for heat of combustion to find the heat produced per mole of substance burned, which is measured in units of energy (kJ/mole).

I hope this explanation helps to clarify the formula for you. Let me know if you have any other questions. Happy experimenting!