Ideal Gas Equation

• What do chemists use chemical equations for?

  To work out masses of reactants or products
• What is Avogadro's constant?

  6.022 x $10^{23}$, number of molecules in a mole
• Why does the size of gas molecules not affect total volume?

  Because molecules in a gas are very far apart
• What is the molar volume of a gas at standard temperature and pressure (s.t.p)?

  22.4 dm³
• What is the molar volume of a gas at room temperature and pressure (r.t.p)?

  24 dm³
• What are the conditions for room temperature and pressure (r.t.p)?

  25ºC (298K) and 1 atm (100 kPa)
• What are the conditions for standard temperature and pressure (s.t.p)?

  0ºC (273K) and 1 atm (100 kPa)
• How much volume does 1 mol of O₂ occupy at r.t.p?

  24 dm³
• What volume do 2 mol of CO₂ occupy at r.t.p?

  48 dm³
• What volume does 0.25 mol of N₂ occupy at r.t.p?

  6 dm³
• What equations can be used to determine molar volumes at r.t.p and s.t.p?

  • At r.t.p:
  • Mol of gas = Volume (dm³) / 24
  • Volume (cm³) = Mol of gas × 24,000
  • At s.t.p:
  • Mol of gas = Volume (dm³) / 22.4
  • Volume (cm³) = Mol of gas × 22,400
• How do you calculate the volume occupied by 4.4g of CO at r.t.p?

  Volume = 0.1 mol × 24
• What is the volume occupied by 1.2 dm³ of methane gas at r.t.p?

  0.03 mol × 16 = 0.89 g
• How do you calculate the volume occupied by 170g of NH₃ at r.t.p?

  Volume = 10 mol × 24
• What is the volume occupied by 12 dm³ of SO₂ at r.t.p?

  Volume = 12.05 g × volume
• What are the calculations for the volume of gases at r.t.p?

  1. Volume of 6 mol SO₂ = 144 dm³
  2. Volume of 0.25 mol O₂ = 6 dm³
  3. Volume of 3 mol CO₂ = 72 dm³
  4. Volume of 0.1 mol NH₃ = 2.4 dm³
• What are the calculations for the amount of gas in given volumes at r.t.p?

  1. Amount in 36 dm³ O₂ = 1.5 mol
  2. Amount in 1080 dm³ N₂ = 45 mol
  3. Amount in 4.0 dm³ CO₂ = 0.17 mol
  4. Amount in 1920 cm³ C₂H₁ = 0.8 mol
• What are the calculations for the mass of gases at r.t.p?

  1. Mass of 0.6 dm³ N₂ = 0.021 g
  2. Mass of 84 dm³ N₂O = 3.36 g
  3. Mass of 1920 dm³ SO₂ = 96 g
  4. Mass of 1920 cm³ NO₂ = 0.1 g
• What are the calculations for the number of mol and volume occupied by gases at r.t.p?

  1. 1.282 g SO₂ = 0.04 mol, 0.96 dm³
  2. 1.485 g HCN = 0.05 mol, 1.2 dm³
  3. 200 kg N₂H₂ = 5000 mol, 120,000 dm³
  4. 1.26 g C₂H₁ = 0.04 mol, 0.96 dm³
• What is the ideal gas equation?

  PV = nRT
• What does P represent in the ideal gas equation?

  Pressure (Pa)
• What does V represent in the ideal gas equation?

  Volume (m³)
• What does n represent in the ideal gas equation?

  Number of moles
• What does R represent in the ideal gas equation?

  Gas constant (8.31 J mol⁻¹ K⁻¹)
• What does T represent in the ideal gas equation?

  Temperature (K)
• Why are units important in gas calculations?

  To ensure correct conversions and calculations
• How do you convert pressure from kPa to Pa?

  Multiply by 1000
• How do you convert volume from dm³ to m³?

  Divide by 1000
• How do you convert temperature from °C to K?

  Add 273
• What is the volume of 45 cm² in m³?

  0.000045 m³
• What is the volume of 24 dm³ in m²?

  0.024 m²
• What is the pressure of 40 MPa in Pa?

  40 x $10^{6}$ Pa
• What is the temperature of -196°C in K?

  77 K
• What is the temperature of 1354°C in K?

  1627 K
• What is the temperature of 50°C in K?

  323 K
• What is the temperature of -29°C in K?

  244 K
• What is the temperature of 78°C in K?

  351 K
• How do you find the volume occupied by 2.20g of CO₂ at 298K and 100KPa?

  Use PV = nRT to calculate
• What is the volume occupied by 16.0 g of O₂ at 0°C and 100KPa?

  0.0113 m³
• What is the pressure of 0.842g of N₂ gas at 16°C in a 3.25 dm³ container?

  28915 Pa