What are some common mistakes students make with chemical equations?

1 Answer
May 30, 2014

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.