Question

balanced chemical equations quick check
which parts must be balanced in a chemical equation? (1 point)
numbers of reactant and product atoms
energy on the reactant and product sides
numbers of reactant and product molecules
states of reactants and products

Explanation:

According to the law of conservation of mass, in a chemical reaction, atoms are neither created nor destroyed. So, the number of atoms of each element on the reactant side must equal the number of atoms of each element on the product side. Energy is not balanced in the same sense as atom counts in a simple chemical equation balancing (though energy considerations are important in thermochemistry but not in basic equation balancing). The number of molecules can vary (e.g., in \(2H_2 + O_2=2H_2O\), there are 3 molecules on the reactant side and 2 on the product side). The states of reactants and products (\(s\) - solid, \(l\) - liquid, \(g\) - gas, \(aq\) - aqueous) are just descriptive and not balanced in the atom - counting sense.

Answer:

numbers of reactant and product atoms