AMOUNT OF SUBSTANCE

• What are some specific topics that will be covered in the series?

  Percentage yield, atom economy, ideal gas equation, and empirical formula.
• Why is the mole considered a strange term by some people?

  People often do not know what a mole is and find it confusing.
• How many particles are in one mole?

  1. 023 x $10^{23}$
• Why is the term "mole" frequently used in chemistry?

  It simplifies the description of large quantities of atoms, ions, or molecules.
• In a chemical reaction, how is the mole ratio represented?

  It is represented similarly to algebraic equations, such as a + b = c + d.
• If you have 2 moles of substance A and 1 mole of substance B, how many moles of substance C will be produced if the reaction is A + B → C?


  1 mole of substance C will be produced.
• What is the mole ratio of hydrochloric acid to sodium hydroxide in their reaction?

  The mole ratio is 1:1.
• How do you calculate concentration using moles and volume?

  Concentration equals moles divided by volume.
• What is the unit for concentration in the context of this study material?

  Moles per decimeter cubed (mol/dm³).
• How do you convert centimeters cubed to decimeters cubed?

  You divide by 1000.
• If you have a volume of 50 cm³, what is its equivalent in decimeters cubed?

  0.050 dm³.
• What does the term "Mr" refer to in the context of moles?

  Mr refers to the relative molecular mass.
• What is the mass of one mole of carbon-12?

  12 grams.
• How do you calculate the mass of a molecule using its molar mass?

  One mole of a molecule equals its molar mass in grams.
• What are the two key equations related to moles and concentration?

  1. Concentration = moles / volume
  2. Moles = mass / Mr
• In the example given, what is the first step to calculate the concentration of sodium hydroxide?

  Calculate the moles of hydrochloric acid using its concentration and volume.
• If the concentration of hydrochloric acid is 0.150 mol/dm³ and the volume is 32.10 cm³, how do you find the moles of hydrochloric acid?

  Convert the volume to dm³ and multiply by the concentration.
• Why is it important not to round numbers during calculations?

  Rounding can lead to inaccuracies in the final answer.
• What should you do with your final answer in calculations?

  Provide it to the appropriate precision, often three significant figures.
• What is atom economy?

  Atom economy is a measure of the efficiency of a reaction in terms of how well atoms are utilized.
• What is the ideal gas equation?

  The ideal gas equation relates pressure, volume, temperature, and the number of moles of a gas.
• What is an empirical formula?

  An empirical formula shows the simplest whole-number ratio of atoms in a compound.
• Why is balancing equations important in chemistry?

  Balancing equations ensures that the law of conservation of mass is upheld in a reaction.
• Why are relative atomic masses important in calculations?

  Relative atomic masses are used to calculate the moles and mass of substances in reactions.
• What is the purpose of titration calculations?

  Titration calculations determine the concentration of an unknown solution by reacting it with a standard solution.
• What is the standard form of the number mentioned in the study material?

  1. 85 * 10^3
• Why should you avoid rounding numbers during calculations?

  Rounding can lead to incorrect final answers.
• How many decimal places should you write down your answer to maintain accuracy?

  At least seven decimal places.
• What is the appropriate precision for the final answer in calculations?

  Three significant figures.
• What should you do if you make a calculator error during calculations?

  Ensure all working out is clear to avoid losing marks.
• What is the mole ratio of hydrochloric acid to sodium hydroxide in the given reaction?

  1. 1 ratio.
• If you have 0.04815 moles of hydrochloric acid, how many moles of sodium hydroxide will react?

  0.04815 moles of sodium hydroxide.
• Why is it important to lay out calculations clearly?

  To ensure the marker can follow your reasoning and award marks.
• What is the formula to calculate the concentration of sodium hydroxide?

  Concentration = moles / volume.
• If you have 0.04815 moles of sodium hydroxide and a volume of 25 dm³, what is the concentration?

  0.001926 moles per dm³.
• What is the concentration unit for sodium hydroxide?

  Moles per decimeter cubed.
• What are the steps to calculate moles from mass for ammonium sulfate?

  1. Use the formula: moles = mass / molar mass (Mr).
  2. Calculate the molar mass of ammonium sulfate.
  3. Divide the mass (3.14 g) by the molar mass to find moles.
• How do you calculate the moles of sodium hydroxide that reacted with ammonium sulfate?

  Multiply the moles of ammonium sulfate by 2 (1:2 ratio).
• What is the final concentration of sodium hydroxide calculated in the example?

  1. 21 moles per decimeter cubed.
• What is the reaction equation for the preparation of zinc chloride from zinc oxide and hydrochloric acid?

  • Zinc oxide + Hydrochloric acid → Zinc chloride + Water
  • Molar ratio: 1:2