Answer: mass
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
For example in the balanced equation :
[tex]2H_2+O_2\rightarrow 2H_2O[/tex]
Thus in the reactants, there are 4 atoms of hydrogen and 2 atoms of oxygen.Thus there will be 4 atoms of hydrogen, and 2 atoms of oxygen in the product as well.
Thus there will be equal mass on both sides of the balanced equation.
