Explain how the law of conservation of mass necessitates our balancing all chemical equations.

The law of conservation of mass states that energy can neither be created, nor destroyed. It applies to all the chemical equations because everything is about matter. Changing one chemical to another, changing forms, shapes, colors, types to other ones. But in each and every single process of this universe, nothing is created or destroyed. It's just the simplest to the most complex transfers of energy throughout the universe.
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