3.2.1 Moles

• What are chemical amounts measured in?

  Moles.
• What is the symbol for the unit mole?

  Mol.
• The mass of one mole of a substance in grams is numerically equal to what?

  Its relative formula mass.
• One mole of a substance contains the same number of the stated particles, atoms, molecules or ions as one mole of any other substance.
• The number of atoms, molecules or ions in a mole of a given substance is the what?

  Avogadro constant.
• What is the value of the Avogadro constant?

  6.02 x 10^23 per mole.
• What is the formula that links mass, moles, and Mr?

  Mass = moles x Mr.
• What is the mass of 1 mole of sodium (Na)?

  23g.
• What is the mass of 0.25 moles of carbon dioxide (CO2)? (Ar of C is 12, Ar of O is 16)

  11g.
• How many moles are there in 72g of water (H2O)? (Ar of H is 1, Ar of O is 16)

  4 moles.
• How many moles are there in 10.2g of ammonia (NH3)? Give your answer as a decimal. (Ar of N is 14, Ar of H is 1)

  0.6 moles.
• 0.040 moles of an unknown compound is found to have a mass of 3.28 g. Find the relative formula mass of the compound.

  82.
• 1.4 moles of an unknown compound is found to have a mass of 39.2 g. Find the relative formula mass of the compound.

  28.
• What is the mass of 4 moles of nitrogen gas (N2)? (Ar of N is 14)

  112g.