Limiting reactants

• What are limiting reactants?

  Reactants that determine the amount of product
• How do limiting reactants affect calculations?

  They determine the mass of the product formed
• What happens when calcium carbonate reacts with hydrochloric acid?

  Produces calcium chloride, water, and carbon dioxide
• What indicates that a reaction is taking place between calcium carbonate and hydrochloric acid?

  Solid calcium carbonate disappears and gas bubbles form
• What signifies that a reactant is limiting?

  The reaction stops when it is used up
• What is the state of hydrochloric acid when calcium carbonate is used up?

  It is in excess
• Why is it important to identify the limiting reactant?

  It determines the maximum amount of product
• What happens if more calcium carbonate is added to the reaction?

  More fizzing occurs until it is used up
• What happens if more hydrochloric acid is added?

  Nothing happens without calcium carbonate
• What is combustion in the context of sodium burning in air?

  Reaction with oxygen
• What is assumed about oxygen when sodium is burned in air?

  Oxygen is in excess
• What is the first step in calculating the mass of sodium oxide produced?

  Write and balance the chemical equation
• What equation is used to calculate moles?

  Moles = mass / molar mass
• How many moles of sodium are in 115 grams?

  5 moles
• What is the mole ratio of sodium to sodium oxide?

  2 to 1
• How many moles of sodium oxide are produced from 5 moles of sodium?

  2.5 moles
• What is the formula to find the mass of sodium oxide?

  Mass = moles × molar mass
• What is the molar mass of sodium oxide (Na₂O)?

  62 g/mol
• What is the mass of 2.5 moles of sodium oxide?

  155 grams
• What are the products of the reaction between hydrochloric acid and calcium carbonate?

  • Calcium chloride
  • Water
  • Carbon dioxide
• What is the significance of identifying limiting and excess reactants in a chemical reaction?

  • Limiting reactant determines product yield
  • Excess reactant remains after the reaction
• What steps are involved in calculating the mass of a product from a limiting reactant?

  1. Write and balance the equation
  2. Calculate moles of limiting reactant
  3. Use mole ratio to find moles of product
  4. Calculate mass of product using moles and molar mass