Limiting Reactants

• What is the main topic discussed in the video?

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

  It produces calcium chloride, water, and carbon dioxide
• What observable signs indicate that a reaction is taking place between hydrochloric acid and calcium carbonate?

  The solid calcium carbonate disappears and bubbles of gas are produced
• What does it mean when the fizzing in the reaction slows down and eventually stops?

  It indicates that one of the reactants has been completely used up
• What do we call the reactant that limits the amount of product that can be produced?

  Limiting reactant
• What is the role of hydrochloric acid in the reaction with calcium carbonate?

  It is in excess and does not limit the amount of product produced
• What happens if more calcium carbonate is added to the reaction?

  More fizzing occurs as more products are made until the calcium carbonate is used up
• 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?

  It means reacting with oxygen
• In the example of sodium burning in air, which reactant is considered to be in excess?

  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 molar mass (mr) of sodium?

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

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

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

  1. 5 moles
• What is the mass of sodium oxide produced from 2.5 moles?

  155 grams
• How do you find the molar mass of sodium oxide (Na2O)?

  By calculating 2 times the molar mass of sodium plus the molar mass of oxygen
• What is the molar mass of sodium oxide?

  62 g/mol
• 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. Use the mole ratio from the balanced equation to find moles of the product.
  4. Calculate the mass of the product using the formula mass = moles × mr.