Limiting Reactant

• What is the focus of today's video?

  The video focuses on limiting reactants and their effect on calculations.
• What happens when hydrochloric acid reacts with calcium carbonate?

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

  The solid calcium carbonate will slowly disappear and bubbles of gas will be given off.
• What indicates that one of the reactants has been completely used up in the reaction?

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

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

  Hydrochloric acid is in excess.
• Why is it important to identify the limiting reactant in a chemical reaction?

  Because the amount of product formed depends entirely on the limiting reactant.
• What happens if more calcium carbonate is added to the reaction?

  More fizzing will occur as more products are made until the calcium carbonate is used up again.
• What will happen if more hydrochloric acid is added after all calcium carbonate is used up?

  Nothing will happen because there is no calcium carbonate to react with.
• What is combustion in the context of sodium burning in air?

  Combustion means reacting with oxygen.
• In the example of sodium burning in air, which reactant is considered the limiting reactant?

  Sodium is the limiting reactant.
• What is the first step in calculating the mass of sodium oxide produced?

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

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

  The molar mass of sodium is 23 g/mol.
• How many moles of sodium are in 115 grams?

  There are 5 moles of sodium.
• What is the mole ratio between sodium and sodium oxide in the balanced equation?

  The ratio is 2:1.
• How many moles of sodium oxide are produced from 5 moles of sodium?

  1. 5 moles of sodium oxide are produced.
• How do you calculate the mass of sodium oxide produced?

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

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

  The mass is 155 grams.
• What are the key steps in calculating the mass of a product from a limiting reactant?

  1. Write and balance the chemical equation.
  2. Calculate the number of moles of the limiting reactant.
  3. Determine the mole ratio from the balanced equation.
  4. Calculate the number of moles of the product formed.
  5. Calculate the mass of the product using mass = moles × mr.