What is a Limiting Reactant?

• What is the focus of today's video?

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

  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 is a limiting reactant?

  The reactant that is completely consumed first
• Why is the limiting reactant important in chemical reactions?

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

  More fizzing occurs until calcium carbonate is used up
• What is implied when a question states that one reactant is in excess?

  The other reactant is the limiting reactant
• What is combustion in the context of sodium burning in air?

  Reacting with oxygen
• How do you calculate the number of moles of sodium?

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

  23 g/mol
• How many moles of sodium are produced from 115 grams?

  5 moles
• What is the mole ratio between sodium and sodium oxide?

  2:1
• 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?

  Using mass = moles × mr
• 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 steps to calculate the mass of a product from a limiting reactant?

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