# How do you write chemical equations for combustion reactions?

## So I have solid barium, solid boron, liquid acetone ${C}_{3} {H}_{6} O$, and liquid octane ${C}_{8} {H}_{18}$. I know that a combustion reaction results in $C {O}_{2}$ + ${H}_{2} O$, but I'm just confused on what the text is saying with the formula for combustion being A + ${O}_{2}$ $\rightarrow$ AO.

Mar 23, 2016

The combustion of octane ${C}_{8} {H}_{18}$ follows this reaction
$2 {C}_{8} {H}_{18} + 25 {O}_{2} \to 16 C {O}_{2} + 18 {H}_{2} O$

#### Explanation:

A combustion reaction takes a hydrocarbon and burns it in oxygen to release carbon dioxide and water. A hydrocarbon is a molecule that contains carbon and hydrogen.

The basic equation looks like this.

The combustion of propane ${C}_{3} {H}_{8}$ follows this reaction

${C}_{3} {H}_{8} + 5 {O}_{2} \to 3 C {O}_{2} + 4 {H}_{2} O$

The combustion of pentane ${C}_{5} {H}_{12}$ follows this reaction

${C}_{5} {H}_{12} + 8 {O}_{2} \to 5 C {O}_{2} + 6 {H}_{2} O$

The combustion of octane ${C}_{8} {H}_{18}$ follows this reaction

$2 {C}_{8} {H}_{18} + 25 {O}_{2} \to 16 C {O}_{2} + 18 {H}_{2} O$

Combustion is when a substance reacts quickly with oxygen producing heat and light.

#### Explanation:

The general equation for combustion is:

$A + {O}_{2} \to A O$

Magnesium is an example of an element that can undergo a combustion reaction. The reaction of magnesium and oxygen produces a very bright light and quite a bit of heat, burning at a temperature of 3,100 °C.

Here is a quick demonstration showing the combustion of magnesium.

Hope this helps!