How would you figure out how much energy 27 kg of gasoline would provide you with?

Question

I'm curious - how much energy does 27 (for example) kg of gas give you? How can you figure this out? Is there a formula? And speaking of energy...if you happened to weigh, maybe, 60 kilos and ran for 30 min, how many kilos of apples would you have to eat to compensate for the energy you used?

Thanks in advance!

A.

Answer 1

You look it up on the internet. Use google, search for "energy gasoline".

So 27 kg / 740 kg/m³ = 0.036 m³ = 36 L

36 L * 34.8 MJ/L = 1270 MJ

Wikipedia:

"Gasoline contains about 34.8 MJ/L or 132 MJ/US gallon. This is about 9.67 kWh/L or 36.6 kWh/US gallon. This is an average; gasoline blends differ, therefore actual energy content varies from season to season and from batch to batch, by up to 4% more or less than the average, according to the US EPA."

"The weight-density of gasoline is about 740 kg/m³ (6.175 lb/US gal; 7.416 lb/imp gal)."

Answer 2

There may be just that sort of formula, however I have never come across anything that can tell you that. You would have to know how pure the gas is to know how efficiently it will burn what you are using to burn it and many other factors that would need to be controlled are we talking about the absolute best possible conditions or what? As far as the apples go that would also depend on the condition of the person how in shape they are if they have any health defects, etc...

Answer 3

Laboratory tests determine the high and low heating values of a particular fuel (whether or not heat is obtained by condensing water vapor in the exhaust).  A gallon of gasoline (hydrocarbon) produces about a gallon of condensed water.  The heating values will depend upon octane, etc.

Answer 4

The maximum energy that can be provided by a given amount of gasoline is the energy released by the complete combustion of the hydrocarbon chemicals in gasoline. Determining that energy is a thermochemistry problem.

Gasoline is a mixture of a number of hydrocarbons containing 5 to 10 carbon atoms in each molecule. You could write the equations for the combustion of each of those hydrocarbons and determine the energy released by breaking the hydrocarbon molecules into carbon and hydrogen atoms. You would also need to determine the energy required to form the resulting compounds, probably carbon dioxide and water. From that you can determine the net energy released by the combustion of each hydrocarbon compound and add together the results. Energy of formation data is available for many compounds. It may also be possible to base calculations on the energy of the chemical bonds between individual atoms. Whatever data is available for individual chemicals and chemical bonds was originally determined by calorimetry experiments. In a calorimetry experiments, chemical reactions are caused to take place in a closed and heavily insulated container called a calorimeter. The resulting release of energy as heat is calculated from the measured change in the temperature of the material inside the calorimeter.

Rather than calculate the energy available from gasoline, a calorimeter could be used to determine the energy released experimentally. That is the way the energy available from food is determined. The food is caused to undergo chemical combustion in a calorimeter. The energy contained in the food, measured in calories can then be determined. One food calorie equals about 4187 joules. The energy listed for food is about 85% of the energy determined by calorimetry to account for the digestive process not completely releasing all of the available energy. That means that 85% of the energy in our food is made