Balancing Chemical Equations

____ stays the same no matter where you are

mass

Law of Conservation of Mass

states that substances cannot be created or destroyed, must be equal to the mass of the products

Why must chemical equations be balanced?

They must obey the Law of Conservation of Mass that states that matter cannot be created or destroyed, it is conserved. Atoms are never lost or gained in chemical reactions, they are rearranged. The mass of the reactants must equal the mass of the products.

Scientific Law

a generalization about how the physical universe works

coefficient

a number that is placed in front of a chemical formula

subscript

a number written below and to the right of an element's symbol in a chemical formula to denote the number of that atom present

chemical formula

a shorthand way to use element symbols and numbers to represent a substance

weight

changes depending on how much gravity is present

Only ____ are changed when balancing equations

coefficients

chemical equation

representation of a chemical reaction that uses chemical formulas to show relationships between the reactants and products

reactants

starting materials in a chemical equation

products

substances formed from a chemical reaction

If a symbol has no _____, only ______ atom of that element is present

subscript, one

Mass

the amount of matter a substance has