What are some common mistakes students make with chemical equations?

Question

Owen Ambrose · Accepted Answer

The most frequent error is probably assuming that diatomic molecules in a chemical equation are already balanced.

This is an illustration of what I mean:

#C_6H_12O_6 -> C_2H_5O_6 + CO_2#

In balance, 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.

Peyton Adams · Answer

undefined Some common mistakes students make with chemical equations include:

1. Incorrect balancing of equations.
2. Forgetting to include states of matter (solid, liquid, gas, aqueous) for reactants and products.
3. Misidentifying reactants and products.
4. Failing to follow the law of conservation of mass.
5. Misinterpreting coefficients as subscripts or vice versa.
6. Not properly representing polyatomic ions.
7. Neglecting to simplify coefficients when balancing equations.