A balanced chemical equation has an equal number of atoms of each element on both sides of the equation. To check if an equation is balanced, count the number of atoms of each element on each side of the equation and make sure they are equal.

For example, consider the following equation:

$$2H_2 + O_2 → 2H_2O$$

On the left side of the equation, there are 4 hydrogen atoms and 2 oxygen atoms. On the right side of the equation, there are also 4 hydrogen atoms and 2 oxygen atoms. Therefore, this equation is balanced.

Here are some tips for balancing chemical equations:

* Start by balancing the elements that appear only once on each side of the equation.

* If an element appears in a compound, balance the compound as a whole.

* Don't change the subscripts of any atoms.

* You may need to add coefficients to some of the compounds in the equation to balance it.

Once you have balanced an equation, double check your work to make sure that all of the atoms are balanced.