Limiting Reactants

• What is the main topic discussed in the video?

  Limiting reactants and their effect on calculations
• 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?

  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
• What do we call the reactant that limits the amount of product produced?

  Limiting reactant
• What is the status of hydrochloric acid when all calcium carbonate has been used up?


  It 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 when calcium carbonate is the limiting reactant?

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

  Reacting with oxygen
• In the example given, which reactant is assumed to be in excess when sodium is burned in air?

  Oxygen
• 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?

  Using the equation moles = mass / mr
• What is the mass of sodium used in the example?

  115 grams
• What is the molar mass (mr) of sodium?

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

  5 moles
• What is the 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?

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

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

  62
• 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. Identify the limiting reactant.
  2. Write and balance the chemical equation.
  3. Calculate the number of moles of the limiting reactant.
  4. Use the mole ratio from the balanced equation to find moles of the product.
  5. Calculate the mass of the product using mass = moles * mr.