law of conservation mass

• The law of conservation of mass tells us that matter is neither created nor destroyed in any chemical reaction
• The total mass of the reactants must be equal to the total mass of the products
• Balancing chemical equations


  1. Count the number of atoms in the reactants

  2. Compare the number of atoms in the products

  3. Make the number of atoms equal
• If the number of atoms is not equal, the equation is not balanced and does not follow the law of conservation of mass
• Atomic mass


  The mass of the atom, usually with decimal values
• Atomic masses of common elements

  • Hydrogen 1
  • Helium 4
  • Lithium 7
  • Beryllium 9
  • Boron 11
  • Carbon 12
  • Nitrogen 14
  • Oxygen 16
  • Fluorine 19
  • Neon 20
• Calculating mass of reactants and products

  1. Multiply the number of atoms by the atomic mass

  2. Add up the masses of all the reactants

  3. Add up the masses of all the products
• The mass of the reactants is equal to the mass of the products, following the law of conservation of mass
• The balanced equations follow the law of conservation of mass, with the total mass of reactants equal to the total mass of products