Do all fuels produce carbon dioxide, water and energy when burnt or combusted?
Answer:
It depends on the oxidizing gas present in the environment where the complete combustion took place.
In a complete combustion reaction, a compound reacts with an oxidizing element (such as oxygen or fluorine) and the products are compounds of each element in the fuel with the oxidizing element.
Examples:
CH4 + 2O2 → CO2 + 2H2O + heat
CH2S + 6F2 → CF4 + 2HF + SF6 + heat
In the large majority of the real world uses of combustion, the oxygen (O2) oxidant is obtained from the ambient air and the resultant flue gas from the combustion will contain nitrogen:
CH4 + 2O2 + 7.52N2 → CO2 + 2H2O + 7.52N2 + heat
Remember that in reality, combustion processes are never complete. Carbon-based fuel, for instance, will always have unburned carbon (or soot) and carbon monoxide (CO) as by-products.
--------------------
As for your question on what this statement means:
'In complete combustion, the gas burns a clean blue flame'
The flames that most people find familiar usually have two colors, blue and a yellowish-orange. The blue color comes from the burning of the fuel vapor, specifically a hydrocarbon fuel. (The color is indicative of a reaction involving a C-H molecule.)
However, you can't always see this region. In many cases the reaction zone is hidden by the very bright yellowish-orange upper portion of the flame. This is the region in which unburned carbon particles are being heated. This unburned carbon is more commonly called soot. (It can be found all over the inside of a well used fireplace.)
The 'gas' mentioned in the statement you gave is supposedly a hydrocarbon gas fuel, like methane.
if the fuel is an alkane, it should produce water and CO2 as products (that is, for complete combustion)...
The answers post by the user, for information only, FunQA.com does not guarantee the right.
More Questions and Answers: