Conservation of mass and balanced chemical equations

• The law of conservation of mass states that no atoms are lost or made during a chemical reaction, so the mass of the products equals the mass of the reactants
• Chemical reactions can be represented by symbol equations which are balanced in terms of the numbers of atoms of each element involved on both sides of the equation
• Subscript (little numbers) within a formula means that there are so many atoms of that element, or elements if it is in brackets
• Normal script (big numbers) before a formula mean that every atom of each element in that formula are all being multiplied by that amount (eg. 2H2O, 4 atoms of hydrogen, 2 atoms of oxygen)