Calculating RFM / Mr

  1. 126.8
  2. 73.8
  3. 132.1
  4. 329.1

Mass and moles

  1. 11.7 / 58.5 = 0.2 mol
  2. 24.2 / 44 = 0.55 mol
  3. 236.16 / 73.8 = 3.2 mol
  4. 0.06605 / 132.1 = 5 x 10-4 or 0.0005 mol

Solutions and concentration

  1. Moles = 0.1 x 2 = 0.20 mol
  2. Moles = 2 x 0.025 = 0.050 mol
  3. Moles = 0.5 / 40 = 0.0125                          Concentration = 0.0125 / 0.25 = 0.05 mol dm-3
  4. Volume = mol / concentration = 3 / 0.15 = 20 dm3

Molar gas volume

  1. Moles = 0.24 / 24 = 0.01 mol
  2. Moles = 3.2 / 24 = 0.133 mol
  3. Moles = 0.24 / 24 = 0.01 mol
  4. Moles = 0.072 / 24 = 3 x 10-3 or 0.003 mol
  5. Volume = 2.5 x 24 = 60 dm3
  6. Volume = 0.03 x 24 = 0.72 dm3
  7. Volume = 44 x 24 = 1056 dm3
  8. Volume = 0.12 x 24 = 2.88 dm3

Mixed calculations

  1. Moles = 0.06 / 24 = 2.5 x 10-3      mass = moles x Mr = 2.5 x 10-3 x 16 = 0.04g
  2. Moles = mass / Mr = 13.2 / 44 = 0.3               Volume = 0.3 x 24 = 7.2 dm3
  3. Mr = mass / mole = 6.744 / 0.08 = 84.3                 Relative mass CO3 = 60 84.3 – 60 = 24.3              This is the mass of Mg, therefore formula is MgCO3
  1. Moles = volume x concentration = 0.3 x 0.5 = 0.15

Volume of ammonia = 0.15 x 24 = 3.6 dm3

Ionic compounds answers

Types of reaction answers

Types of equation answers

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