Chemistry topic 1?

• What is the purpose of PAG 1 in A Level Chemistry?

  PAG 1 focuses on Moles Determination.
• What are the suggested practicals for PAG 1 - Moles Determination?

  • Determination of the composition of copper(II) carbonate
  • Determination of the relative atomic mass of magnesium
  • Determination of the formula of magnesium oxide
• How is the number of moles calculated in the suggested practicals?

  By calculating from experimental data.
• In the gas volume measurement experiments, what is produced during the reaction?

  A gas is produced.
• How is the final answer determined in gas volume experiments?

  Using the stoichiometric ratio of the chemical reaction.
• What is the suggested practical for determining the formula of magnesium oxide?

  Combustion of a known mass of magnesium.
• What is measured to determine the ratio of elements in magnesium oxide?

  The mass of magnesium and the mass of magnesium oxide product.
• How can the number of water of crystallizations in hydrated salts be calculated?

  By heating them to a constant mass and measuring the decrease in mass.
• What is added to the conical flask in the copper(II) carbonate experiment?

  An excess of sulfuric acid.
• What is the setup for determining the composition of copper(II) carbonate?

  A measuring cylinder in a water bath connected to a conical flask.
• How is the volume of carbon dioxide measured in the experiment?

  By recording the final volume in the measuring cylinder.
• What is the equation to find the number of moles of CO₂ produced?

  Using the measured volume, v, with the equation: $n =$$\frac{v}{24.0}$
• Under what conditions is the calculation for moles of gas correct?

  At room temperature and pressure (101 kPa or 1 atmosphere).
• What is the molar ratio for the reaction of CuCO₃ with H₂SO₄?

  1. 1 for CuCO₃ to CO₂.
• How is the mass of CuCO₃ determined in the experiment?

  Using the equation: $m =$$n \times M_r$
• What is a potential source of error in the copper(II) carbonate experiment?

  Some carbon dioxide may escape before inserting the bung.
• How can the escape of carbon dioxide be minimized in the experiment?

  By inserting the bung immediately after adding the acid.
• What is another potential issue during the reaction in the experiment?

  Some of the copper carbonate may not react.
• How can the reaction be improved to ensure all copper carbonate reacts?

  By swirling the conical flask during the reaction.
• What is the volume of 1 mole of gas at room temperature and pressure?

  24.0 dm³
• Under what conditions is the calculation of gas volume at 24.0 dm³ valid?

  When the reaction is completed at room temperature and pressure (101 kPa or 1 atmosphere)
• What should be used if the calculation is completed under conditions that are not RTP?

  A rearranged form of the ideal gas equation
• What is the overall equation for the reaction between copper carbonate and sulfuric acid?

  CuCO₃ + H₂SO₄ → CuSO₄ + H₂O + CO₂
• What is the molar ratio for CuCO₃ to CO₂ in the reaction?

  1. 1
• How can the mass of CuCO₃ be determined?

  Using the formula m = n x M_r
• Why do we need to determine the percentage by mass of CuCO₃ in the original sample?

  To understand the composition of the sample
• What is a potential source of error when measuring the reaction of copper carbonate?

  Some carbon dioxide may escape from the conical flask
• How can the escape of carbon dioxide be avoided during the reaction?

  By inserting the bung as soon as the acid is poured into the conical flask
• What should be done to ensure that all copper carbonate reacts?

  Swirl the conical flask to ensure the contents are sufficiently mixed
• What can happen to carbon dioxide during the reaction?

  It may dissolve in the water
• What equipment can be used to measure the volume of CO₂ produced?

  A gas syringe
• What is a potential error related to the weighing of copper carbonate?

  Some copper carbonate may remain on the weighing apparatus
• How can the exact amount of copper carbonate added to the conical flask be determined?

  By weighing the weighing apparatus with and without copper carbonate
• What is the procedure for determining the relative atomic mass of magnesium?

  1. Set up apparatus with a measuring cylinder in a water bath connected to a conical flask.
  2. Measure a known mass of magnesium and add it to the flask.
  3. Add excess sulfuric acid and insert the stopper immediately.
  4. Collect the produced hydrogen gas in the measuring cylinder.
  5. Record the final volume of hydrogen gas.
• What is the overall equation for the reaction between magnesium and sulfuric acid?

  Mg + H₂SO₄ → MgSO₄ + H₂
• What is the molar ratio for Mg to H₂ in the reaction?

  1. 1
• How can the number of moles of H₂ produced be calculated?

  Using the measured volume with the equation for gas volume
• What is a potential source of error when measuring hydrogen gas in the reaction?

  Some hydrogen may escape from the conical flask
• How can the escape of hydrogen gas be minimized during the reaction?

  By inserting the bung as soon as the acid is poured into the conical flask
• What should be done to ensure that all magnesium reacts?

  Use magnesium powder instead of ribbon and ensure excess acid is added