Lavoisier's law: Balancing of equations

Lavoisiers law and balancing equations

The chemicals we have at the start of a reaction are called reactants. When a chemical reaction takes place the atoms in these substances are rearranged to form new chemicals. The substances formed in a reaction are called products.

Key points to remember:

In chemical reactions new substances are made.
A reaction can be summarised in a word equation or a symbol equation.
The total mass of the reactants is the same as the total mass of products in a reaction
A symbol equation must be balanced as no atoms are created or destroyed.
You can never change a formula when balancing an equation. You can only put a number in front of a formula.
No atoms are created or destroyed in a chemical reaction.
There should be the same number of atoms of each type of element each side of the equation.
Magnesium + Oxygen ----> Magnesium oxide