Limiting Reactants

• What is the main topic of today's video?

  Limiting reactants
• What happens when hydrochloric acid reacts with calcium carbonate?

  It produces calcium chloride, water, and carbon dioxide
• How can we observe that a reaction is taking place between hydrochloric acid and calcium carbonate?

  Solid calcium carbonate disappears and gas bubbles form
• What indicates that one of the reactants has been completely used up in the reaction?

  The reaction stops and fizzing slows down
• What do we call the reactant that limits the amount of product produced?

  Limiting reactant
• What is the status of hydrochloric acid when calcium carbonate is the limiting reactant?

  Hydrochloric acid is in excess
• What happens if more calcium carbonate is added to the reaction?

  More fizzing occurs until calcium carbonate is used up
• What occurs if more hydrochloric acid is added without calcium carbonate?

  Nothing happens as there is no reactant
• What is combustion in the context of sodium burning in air?

  Reacting with oxygen
• What is the first step in calculating the mass of sodium oxide produced?

  Write and balance the chemical equation
• How do you calculate the number of moles of sodium?

  Use moles = mass / mr
• What is the molar mass (mr) of sodium?

  23
• How many moles of sodium are in 115 grams?

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

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

  2.5 moles
• How do you calculate the mass of sodium oxide produced?

  Use mass = moles * mr
• What is the molar mass of sodium oxide (Na₂O)?

  62
• 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 the limiting reactant in chemical reactions?

  • Determines the maximum amount of product
  • Reactant that is completely consumed
  • Affects the yield of the reaction
• What is the process for 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