Fuels

​A combustion reaction involves two important reactants: fuel (a combustible substance) oxygen gas.(oxidizer)

! In all cases, the combustible material reacts with oxygen, and produces metallic or non-metallic oxides. These reactions are highly exothermic since the molecules produced are energetically more stable than the reactant fuel and oxygen gas.

​Nearly all metals react with oxygen to form metallic oxides.

​2Mg(s) + O2(g) → 2MgO(s) ΔH is negative

​Less reactive metals also combine with oxygen. For example, iron, copper, and silver react with oxygen to form their own metallic oxides.

​4Ag(s) + O2(g) → 2Ag2O(s) ΔH is negative (praktiski notiek ļoti lēni)

​Combustion of non-metals

​onversely, many non-metals react with oxygen to form non-metallic oxides. These oxides do not have fixed ratios, so these combustion reactions can produce several different product oxides for the same non-metal fuel.

​Combustion of organic compounds In the complete combustion of methane gas, seen below, both the carbon and hydrogen atoms in the reactant molecules experience a gain in oxygen, and are fully oxidised.



CH4(g) + O2(g) → CO2(g) + H2O(g) ∆H is negative

​All organic compounds, especially those that contain only hydrogen and carbon (hydrocarbons), as well as alcohols, easily undergo complete combustion reactions that produce only carbon dioxide and water.

​Combustion of organic compounds

​CH3CH2OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g) ∆H is negative

​https://youtu.be/UfXXQRAvLi0

​Incomplete combustion of organic compounds