Moles and volumes

• 1 cm3 = 1 ml
• 1 dm3 = 1000cm3 = 1000ml = 1 liter
• mol = conc x vol (dm3)
• A standard solution is a solution of known concentration. Standard solutions are prepared by dissolving an exact mass of the solute in a solvent and making up the solution to an exact volume
• At the same temp and pressure, equal volumes of different gases contain the same number of molecules
• The molar gas volume $V_m$ is the volume per mole of gas molecules at a stated temp and pressure
• At RTP (room temp and pressure), 1 mole of gas molecules has a volume of approx. 24.0 dm3

  Therefore, at RTP, the molar gas volume = 24.0 dm3mol-1
• mol = vol/molar gas vol
• At RTP

  mol = vol dm3/24
• Assumptions for the molecules making up an ideal gas:

  • random motion
  • elastic collisions
  • negligible size
  • no intermolecular forces
• Ideal gas equation:

  pV = nRT
• The ideal gas constant is R = 8.314 Jmol-1K-1
• pV = nRT

  Pressure = Pa

  Volume = m3

  Amount of gas molecules = mol

  Ideal gas constant = 8.31 Jmol-1K-1

  Temperature = K
• cm3 to m3 = x10^-6
• dm3 to m3 = x10^-3
• degrees C to K = +273
• KPa to Pa = x1000