What is the law of conservation of mass? how is it related to balancing chemical equations

The law of conservation states that matter can't be created or destroyed in a chemical reaction. When balancing an equation, both sides need to be equal. If both sides don't have the same amount of atoms for each element, it is unbalanced

The law states that matter cannot be created or destroyed. It's related to balancing equations because it wouldn't make sense to have an uneven number of atoms of each element on each side. It has to be the same, and to be the same we balance them.