Which of the following about a balanced chemical reactions is NOT true?
O A properly written chemical equation will include the states of matter
for every substance in the reaction.
O The number of atoms of each element must be the same for both
reactants and products.
A balanced chemical equation must follow the Law of Conservation
of Matter
A balanced chemical equation must always include coefficients on
every reactant and product.

A balanced chemical equation must always include coefficients on every reactant and product.

Explanation:

A balanced chemical equation does not need to include coefficients on every reactant and product.

For example, below is a balanced chemical equation in which the reactants and the products have no coefficients whatsoever:

NaOH(aq) + HCl (aq) > NaCl (s) + H2O (l)

Of course, a properly written chemical equation must include the states of matter of all the substances in the reaction and the number of atoms of each element must balance both in the reactant and product sides of the equation. Generally, a balanced chemical equation must obey the law of conservation of matter which opines that matter can neither be created nor destroyed but can only be converted from one form to another.

Hence, that a balanced chemical equation must always include coefficients on every reactant and product is not true.