IB Chemistry HL Topic 1

Flashcards for topic 1 objectives.

15 cards   |   Total Attempts: 182
  

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1.1.1: Apply the mole concept to substances.
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.
1.1.2: Determine the number of particles and the amount of substance (in moles).
Convert between the amount of substance (in moles) and the number of atoms, molecules, ions, electrons and formula units.
Moles = Mass / Molar Mass
1.2.1: Define the terms relative atomic mass (Ar) and relative molecular mass (Mr).
Molar Mass: The mass (in grams) per mole of a substance where C12 is exactly 12g. Molecular Mass: The mass per mole of a substance where C12 is exactly 12g.
1.2.2: Calculate the mass of one mole of a species from its formula.
The term molar mass (in g mol–1) will be used.
1.2.4: Distinguish between the terms empirical formula and molecular formula.
Empirical formula: The simplest ratio of the atoms in a chemical compound. Molecular formula: The actual ratio of the atoms in a chemical compound.
1.2.5: Determine the empirical formula from the percentage composition or from other experimental data.
  1. If the percentage composition is given:
    • Consider 100 g of sample, the % of each element becomes its mass.
    • Convert the mass of each element to its amount in moles.
    • Determine simplest whole number ratio – this is its empirical formula.
    • Molecular formula is a whole-number multiple of the empirical formula.
    • Substances react by amounts based on a balanced chemical equation.
1.2.6: Determine the molecular formula when given both the empirical formula and experimental data.
If a molecular formula is given, percentage composition can be calculated.
1.3.1: Deduce chemical equations when all reactants and products are given.
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.
Straightforward.
1.3.3: Apply the state symbols (s), (l), (g) and (aq).
Apply in chemical equations.
1.4.1: Calculate theoretical yields from chemical equations.
Percentage Yield = (Experimental Yield / Theoretical Yield) * 100
1.4.2: Determine the limiting reactant and the reactant in excess when quantities of reacting substances are given.
Limiting reagent: The reagent that limits or determines the amount of product that can be formed in a reaction. The reaction occurs only until the limiting reagent is used up.
1.4.4: Apply Avogadro’s law to calculate reacting volumes of gases.
Answer 13
Avogadros number: 6.02 x 1023
1.4.5: Apply the concept of molar volume at standard temperature and pressure in calculations.
The molar volume of an ideal gas under standard conditions is 2.24 × 10−2 m3 mol−1 (22.4 dm3 mol−1).
1.5.1: Distinguish between the terms solute, solvent, solution and concentration
(g dm–3 and mol dm–3).
Concentration in mol dm–3 is often represented by square brackets around the substance under consideration, for example, [HCl].
Solvent: In a solution, the dissolving medium Solute: In a solution, the dissolved particles. Concentration: The number of moles per unit volume of a substance.