Question

What is the chemical equation to show the combustion reaction of ethanol?

Answer 1

`"C"_2"H"_6"O(l)" + color(orange)3"O"_2"(g)"` `rarr` `color(red)2"CO"_2("g") + color(purple)3"H"_2"O(l")`

Explanation:

`"C"_2"H"_6"O(l)" + "O"_2"(g)"` `rarr` `"CO"_2("g") + "H"_2"O(l")`

Balance the Equation:

Balance the `"C"` and `"H"` first. There are `2` carbon atoms on the left side, and `1` carbon atom on the right side. There are `6` hydrogen atoms on the left side and `2` hydrogen atoms on the right side.

Add a coefficient of `color(red)2` in front of the carbon dioxide, and a coefficient of `color(purple)3` in front of the water.

`"C"_2"H"_6"O(l)" + "O"_2"(g)"` `rarr` `color(red)2"CO"_2("g") + color(purple)3"H"_2"O(l")"`

We now have equal numbers of `"C"` and `"H"` atoms on both sides. However, the `"O"` is not balanced.

We have `7` `"O"` atoms on the right side, and `3` on the left side. Place a coefficient of `color(orange)3` in front of the `"O"_2` on the left side.

`"C"_2"H"_6"O(l)" + color(orange)3"O"_2"(g)"` `rarr` `color(red)2"CO"_2("g") + color(purple)3"H"_2"O(l")`

We now have a balanced equation, with `2` carbon atoms on both sides, `6` hydrogen atoms on both sides, and `7` oxygen atoms on both sides.