Enthalpy of Combustion: Definition & Reactions

• Hydrous Caperilla
In summary, there are two definitions for enthalpy: the heat change when 1 mole of a substance is completely burned or oxidized, according to the textbook, and the heat change when 1 mole of compound is completely burned or oxidized in oxygen, from a website. However, it is unclear how the second definition applies to reactions involving only elements and not compounds.
Hydrous Caperilla
I got two definitions for this enthalpy:

I)Heat change when 1 mole of a substance is completely burned or oxidised(My textbook)
2) Heat change when 1 mole of compound is completely burnt or oxidized in oxygen(From a site)

So if I had this reaction:

H2(g)+1/2 O2(g)---->H20

C(s)+O2(g)------>CO2

How can definition number 2 work for these reactions where there is no compounds.

Hydrous Caperilla said:
I got two definitions for this enthalpy:

I)Heat change when 1 mole of a substance is completely burned or oxidised(My textbook)
2) Heat change when 1 mole of compound is completely burnt or oxidized in oxygen(From a site)

So if I had this reaction:

H2(g)+1/2 O2(g)---->H20

C(s)+O2(g)------>CO2

How can definition number 2 work for these reactions where there is no compounds.
In either definition, they could have worded it "when 1 mole of a substance or compound...".

Hydrous Caperilla
Okay

What is enthalpy of combustion?

Enthalpy of combustion is a measure of the heat energy released when a substance undergoes complete combustion with oxygen.

How is enthalpy of combustion calculated?

Enthalpy of combustion is calculated by measuring the amount of heat released when a substance is completely burned in an oxygen-rich environment, and then dividing that value by the number of moles of the substance that underwent combustion.

What is the significance of enthalpy of combustion?

The enthalpy of combustion is an important property for understanding the energy content of a substance and its potential to release heat. It is also used in determining the energy efficiency of fuels and in designing more efficient combustion processes.

What factors affect enthalpy of combustion?

The enthalpy of combustion is affected by the type of substance being burned, the amount of oxygen present, and the temperature and pressure of the reaction environment. Other factors such as impurities and the presence of water can also impact the enthalpy of combustion.

What are some examples of enthalpy of combustion reactions?

Some common examples of enthalpy of combustion reactions include the burning of fuels such as gasoline, natural gas, and coal, as well as the combustion of organic compounds in biological processes such as respiration. Enthalpy of combustion can also be observed in everyday activities such as cooking and lighting a fire.

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