3.5.2 Calculating volumes of gases in reactions

• What is the significance of molar volume in chemistry?

  • Allows comparison of gas volumes
  • Essential for stoichiometric calculations
• How is the molar volume value determined?

  It comes from experiments comparing gas volumes
• What are the conditions for STP?

  • Standard Temperature: 0°C
  • Standard Pressure: 1 atmosphere
• What is the standard pressure at STP?

  1 atmosphere
• How is the volume of a gas at STP calculated?

  Volume = Moles × Molar Volume
• What is a mole in chemistry?

  A group of molecules, like a dozen
• What does one mole of any gas at STP occupy?

  22.4 litres
• What unit is used to measure the volume of a gas?

  Litres (L)
• What is molar volume?

  Space one mole of gas occupies
• What are the steps to calculate moles of gas at STP?

  1. Write down the volume of the gas
  2. Use the molar volume (22.4 L/mole)
  3. Divide the volume by the molar volume
• If the volume of a gas is 22.4 L at STP, how many moles does it represent?

  1 mole
• What is the formula for the Ideal Gas Law?

  PV = nRT
• What does Avogadro's Law state?

  Equal volumes of gases contain equal moles
• What is the molar volume of a gas at STP?

  22.4 litres
• What are the key concepts related to Avogadro's Law and molar volume?

  • Avogadro's Law: Equal gas volumes contain equal moles
  • Molar volume: Volume occupied by one mole of gas
  • Key Conditions: Same temperature and pressure for Avogadro's Law; STP for molar volume
• What does STP stand for in chemistry?

  Standard Temperature and Pressure
• At what temperature and pressure is molar volume defined?

  0°C and 1 atmosphere pressure
• What is a balanced chemical equation?

  A blueprint for a chemical reaction
• What is the standard temperature at STP?

  0°C
• What is the relationship between volume and moles of gas at STP?

  Volume directly determines the number of moles
• What do coefficients in a balanced chemical equation represent?

  They represent the mole ratios
• In the equation `2H₂ + O₂ -> 2H₂O`, what is the mole ratio of H₂ to O₂?

  2:1
• What is the formula to calculate moles of gas at STP?

  • Moles = Volume of Gas (L) / 22.4 L/mole
• What are the steps to find the mole ratio between two chemicals?

  1. Write out the balanced chemical equation.
  2. Identify the coefficients for the two chemicals.
  3. Express the ratio as "moles of chemical A : moles of chemical B".
• If you have 44.8 litres of oxygen gas at STP, how many moles do you have?

  2 moles
• What does the term 'moles' refer to in gas calculations?

  Number of gas particles
• How do you calculate the number of moles of a gas at STP?

  Divide the volume of gas by molar volume
• What is the formula to calculate the volume of gas?

  Volume = Moles × Molar Volume
• How does the volume of gas affect the number of moles at STP?

  More volume results in more moles
• If you have 0.5 moles of hydrogen gas at STP, what is its volume?

  11.2 L
• What are the definitions of key concepts related to gas volume at STP?

  • Volume: Space a gas occupies (Litres)
  • Moles: Number of gas particles (Moles)
  • Molar Volume: Volume of one mole of gas at STP (22.4 L/mol)
• What is the volume of 2 moles of carbon dioxide gas at STP?

  44.8 L
• When do we use the Ideal Gas Law?

  When gases aren't at standard temperature and pressure
• What are the steps to calculate the volume of oxygen at STP?

  1. Identify the moles of gas.
  2. Use the molar volume at STP.
  3. Calculate the total volume using the formula.
• What law is used to calculate the volume of gas at non-STP conditions?

  Ideal Gas Law
• What is the temperature in Kelvin for 27°C?

  300.15 K
• What does the variable P represent in the Ideal Gas Law?

  Pressure in Pascals (Pa)
• How would you calculate the volume of 2 moles of carbon dioxide gas at STP?

  Volume = 2 moles × 22.4 L/mol
• What unit is volume measured in when using the Ideal Gas Law?

  Cubic meters (m³)
• What is the value of the ideal gas constant R in J/mol·K?

  8.314 J/mol·K