Question

What are some common mistakes students make with chemical equations?

Answer 1

Perhaps the most common mistake is mistaking diatomic molecules as being already balanced in a chemical equation.

Here's an example of what I mean:

`C_6H_12O_6 -> C_2H_5O_6 + CO_2`

Balanced it's

`C_6H_12O_6 -> 2C_2H_5O_6 + 2CO_2`

Students tend to forget that `CO_2` needs to be balanced - the fact that it has a familiar chemical formula doesn't help.

It is also really common to forget that `CO_2` has two atoms of oxygen - this is an essential piece of knowledge when balancing equations. It does not mean that there are two molecules of `CO_2`, it merely means there are two atoms of oxygen present in the molecule.