Topic 1: Quantitative chemistry (12.5 hours)
1.1 The mole concept and Avogadro’s constant (2 hours)
TOK: Assigning numbers to the masses of the chemical elements allowed chemistry to develop into a physical science and use mathematics to express relationships between reactants and products.
| Assessment statement | Obj | Teacher’s Notes | References | |
| 1.1.1 | Apply the mole concept to substances. | 2 | The mole concept applies to all kinds of particles: atoms, molecules, ions, electrons, formula units, and so on. The amount of substance is measured in moles (mol). The approximate value of Avogadro’s constant (L), 6.02 × 1023 mol–1, should be known.TOK: Chemistry deals with enormous differences in scale. The magnitude of Avogadro’s constant is beyond the scale of our everyday experience. | . |
| 1.1.2 | Determine the number of particles and the amount of substance (in moles). | 3 | Convert between the amount of substance (in moles) and the number of atoms, molecules, ions, electrons and formula units. |
1.2 Formulas 3 hours)
| Assessment statement | Obj | Teacher’s notes | References | |
| 1.2.1 | Define the terms relative atomic mass (Ar) and relative molecular mass (Mr). | 1 | ||
| 1.2.2 | Calculate the mass of one mole of a species from its formula. | 2 | The term molar mass (in g mol–1) will be used. | |
| 1.2.3 | Solve problems involving the relationship between the amount of substance in moles, mass and molar mass. | 3 | ||
| 1.2.4 | Distinguish between the terms empirical formula and molecular formula. | 2 | ||
| 1.2.5 | Determine the empirical formula from the percentage composition or from other experimental data. | 3 | Aim 7: Virtual experiments can be used to demonstrate this. | |
| 1.2.6 | Determine the molecular formula when given both the empirical formula and experimental data. | 3 |
1.3 Chemical equations (1 hour)
| Assessment statement | Obj | Teacher’s notes | References | |
| 1.3.1 | Deduce chemical equations when all reactants and products are given. | 3 | Students should be aware of the difference between coefficients and subscripts. | |
| 1.3.2 | Identify the mole ratio of any two species in a chemical equation. | 2 | ||
| 1.3.3 | Apply the state symbols (s), (l), (g) and (aq). | 2 | TOK: When are these symbols necessary in aiding understanding and when are they redundant? |
1.4 Mass and gaseous volume relationships in chemical reactions (4.5 hours)
| Assessment statement | Obj | Teacher’s notes | References | |
| 1.4.1 | Calculate theoretical yields from chemical equations. | 2 | Given a chemical equation and the mass or amount (in moles) of one species, calculate the mass or amount of another species. | |
| 1.4.2 | Determine the limiting reactant and the reactant in excess when quantities of reacting substances are given. | 3 | Aim 7: Virtual experiments can be used here. | |
| 1.4.3 | Solve problems involving theoretical, experimental and percentage yield. | 3 | ||
| 1.4.4 | Apply Avogadro’s law to calculate reacting volumes of gases. | 2 | ||
| 1.4.5 | Apply the concept of molar volume at standard temperature and pressure in calculations. | 2 | The molar volume of an ideal gas under standard conditions is 2.24 × 10−2 m3 mol−1 (22.4 dm3 mol−1). | |
| 1.4.6 | Solve problems involving the relationship between temperature, pressure and volume for a fixed mass of an ideal gas. | 3 | Aim 7: Simulations can be used to demonstrate this. | |
| 1.4.7 | Solve problems using the ideal gas equation, PV = nRT | 3 | TOK: The distinction between the Celsius and Kelvin scales as an example of an artificial and natural scale could be discussed. | |
| 1.4.8 | Analyze graphs relating to the ideal gas equation. | 3 |
1.5 Solutions (2 hours)
| Assessment statement | Obj | Teacher’s notes | References | |
| 1.5.1 | Distinguish between the terms solute, solvent, solution and concentration (g dm–3 and mol dm–3). | 2 | Concentration in mol dm–3 is often represented by square brackets around the substance under consideration, for example, [HCl]. | |
| 1.5.2 | Solve problems involving concentration, amount of solute and volume of solution. | 3 |
