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Chemical Equations

Chemical reactions involves the rearrangement of atoms to beget new chemicals. Often these reactions are captured succinctly in what is called a chemical equation. For example, if we want to show how carbon reacts with oxygen to make carbon dioxide we would write the follow chemical equation.


The plus sign means “reacts with” and the arrow means “to make”. Therefore, we can write this chemical equation in English by saying

Carbon reacts with oxygen to make carbon dioxide

Chemical equations need to balance. If you look at the example above, there are the same number of atoms for each element on each side. The example above is rather simple, however, sometimes it is a little trickeier to tell if an chemical equation is balanced.

In the reaction above we have to look carefully to see if the chemical equation is balanced. Starting on the left we have 1 carbon and 4 hydrogens. Next, there is a 2 which means that we multipl everything by 2 that is next to it. In other words, we do not have 2 oxygen atoms but rather 4 (2 x 2 = 4). After the arrow, we have 1 carbon and 2 oxygen atoms and after the plus sign we have 4 hydrogen atoms (2 x 2 = 4) and 2 oxygen (2 x 1 = 2). If we line everything up you can see that this equation is balanced.

Left SideRight Side
C 1 x 1 = 1 1 x 1 = 1
H 4 x 1 = 4 2 x 2 = 4
O 2 x 2 = 4 2 + (2 x 1) = 4

There are times when you need to balance a chemical equation. This can get really challlenging but we will do a simple example below.

The chemical equation above is not balance as you can see below

Left SideRight Side
H 1 x 2 = 2 1 x 1 = 1
Cl 1 x 2 = 2 1 x 1 = 1

The table above is one process in balancing an equation. We need both sides to equal each other and the simplest way to do this is to multiple the right side by two and we get the following table.

Left SideRight Side
H 1 x 2 = 2 2 x 1 = 2
Cl 1 x 2 = 2 2 x 1 = 2

Below is what our balanced chemical equation looks like.

As mentioned previous, placing the 2 in front of the molecule means multiply everything by 2. Such an example like this is really simple but provides a basic understanding of this process.


Chemical equations can be really fun to deal with once you understand how this works. In the beginning, it can be truly frustrating but perseverance will make the difference.

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