The Mole (Higher Tier)

• What does the term "mole" refer to in chemistry?

  A unit to measure the amount of substance
• How many particles are in one mole of a substance?

  6.02 times 10 to the 23 particles
• What types of particles can a mole refer to?

  Atoms, molecules, ions, or electrons
• If you have one mole of carbon, how many atoms are present?

  6.02 times 10 to the 23 atoms
• What is Avogadro's constant?

  6.02 times 10 to the 23 particles per mole
• Why is Avogadro's constant significant in chemistry?

  It relates mass to relative atomic or formula mass
• What is the mass of one mole of carbon?

  12 grams
• What is the mass of one mole of oxygen?

  32 grams
• How much does one mole of CO2 weigh?

  44 grams
• How do you calculate the number of moles in a sample?

  Mass divided by relative formula mass
• How many moles are in 42.5 grams of ammonia?


  2.5 moles
• What is the relative formula mass (Mr) of ammonia?

  17
• What is the mass of 3 moles of carbon dioxide?

  132 grams
• How do you find the mass of carbon in 3 moles of CO2?

  Multiply 3 moles by 12 grams
• What is the mass of carbon in 3 moles of CO2?

  36 grams
• How much oxygen is in 3 moles of CO2?

  96 grams
• How can chemical equations be interpreted in terms of moles?

  As ratios of reactants and products
• If you start with 2 moles of magnesium, how many moles of hydrochloric acid do you need?

  4 moles
• What is produced when 1 mole of magnesium reacts with hydrochloric acid?

  1 mole of magnesium chloride and hydrogen gas
• What is the relationship between moles and mass in chemistry?

  • 1 mole of a substance contains $6.02 \times 10^{23}$ particles
  • Mass in grams equals the relative atomic or formula mass
  • Formula: Number of moles = Mass / Relative formula mass
• What are the steps to calculate the mass of an element in a compound?

  1. Determine the number of moles of the compound
  2. Multiply by the relative atomic mass of the element
  3. Subtract from the total mass of the compound to find the mass of other elements
• How do chemical equations relate to moles?

  • Chemical equations represent ratios of reactants and products
  • Moles can be used to balance equations
  • Example: 1 mole of magnesium reacts with 2 moles of hydrochloric acid