Conservation of Mass

• What does the law of conservation of mass state?

  Mass is always conserved in chemical reactions; no atoms are lost or made.
• How does the law of conservation of mass apply to chemical reactions?

  The mass of the products equals the mass of the reactants.
• What are the starting materials in a chemical reaction called?

  • Reactants
• What are the chemicals formed in a chemical reaction called?

  • Products
• If 24 grams of magnesium reacts with 71 grams of chlorine, what is the mass of magnesium chloride produced?

  95 grams
• How do you calculate the mass of sodium oxide produced from 92 grams of sodium and 32 grams of oxygen?

  124 grams
• What is the total mass of products if 112 grams of calcium oxide and 88 grams of carbon dioxide are produced?

  200 grams
• How do you find the mass of magnesium oxide that reacted if 73 grams of hydrogen chloride produced 95 grams of magnesium chloride and 18 grams of water?

  40 grams
• What is the process to calculate the mass of a reactant in a chemical reaction?

  1. Identify the total mass of products.
  2. Identify the mass of known reactants.
  3. Subtract the mass of known reactants from the total mass of products to find the unknown reactant mass.