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6. Chemical reactions

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  1. 6.1 Physical and chemical changes

    1. • Identify physical and chemical changes, and describe the differences between them

  2. 6.2 Rate of reaction

    1. • Describe rate changes caused by concentration, gas pressure, solid surface area, temperature and adding/removing catalysts, including enzymes

    2. • State: a catalyst increases the rate of a reaction and is unchanged at the end of a reaction

    3. • Describe practical methods for investigating the rate of a reaction including change in mass of a reactant or a product and the formation of a gas

    4. • Interpret data, including graphs, from rate of reaction experiments

    5. • Describe collision theory in terms of: (a) number of particles per unit volume (b) frequency of collisions between particles (c) kinetic energy of particles (d) activation energy, Ea

    6. • Explain rate changes using collision theory for concentration, gas pressure, solid surface area, temperature and adding/removing catalysts, including enzymes

    7. • State: a catalyst decreases the activation energy, Ea, of a reaction

    8. • Evaluate practical methods for investigating the rate of a reaction including change in mass of a reactant or a product and the formation of a gas

  3. 6.3 Reversible reactions and equilibrium

    1. 6.3.1Some chemical reactions are reversible

      • State: some chemical reactions are reversible as shown by the symbol ⇌

    2. 6.3.2Changing the conditions can change the

      • Describe how changing the conditions can change the direction of a reversible reaction for: (a) the effect of heat on hydrated compounds (b) the addition of water to anhydrous compounds limited to copper(II) sulfate and cobalt(II) chloride

    3. 6.3.3Reversible reaction in a closed system

      • State: a reversible reaction in a closed system is at equilibrium when: (a) the rate of the forward reaction is equal to the rate of the reverse reaction (b) the concentrations of reactants and products are no longer changing

    4. 6.3.4Predict and explain, for a reversible

      • Predict and explain, for a reversible reaction, how the position of equilibrium is affected by: (a) changing temperature (b) changing pressure (c) changing concentration (d) using a catalyst using information provided

    5. 6.3.5Symbol equation for the production of

      • State the symbol equation for the production of ammonia in the Haber process, N2(g) + 3H2(g) ⇌ 2NH3(g)

    6. 6.3.6Sources of the hydrogen (methane) and

      • State the sources of the hydrogen (methane) and nitrogen (air) in the Haber process

    7. 6.3.7Typical conditions in the Haber

      • State the typical conditions in the Haber process as 450 °C, 20 000 kPa/200 atm and an iron catalyst

    8. 6.3.8Symbol equation for the conversion of

      • State the symbol equation for the conversion of sulfur dioxide to sulfur trioxide in the Contact process, 2SO2(g) + O2(g) ⇌ 2SO3(g)

    9. 6.3.9Sources of the sulfur dioxide (burning

      • State the sources of the sulfur dioxide (burning sulfur or roasting sulfide ores) and oxygen (air) in the Contact process

    10. 6.3.10Typical conditions for the conversion

      • State the typical conditions for the conversion of sulfur dioxide to sulfur trioxide in the Contact process as 450 °C, 200 kPa/2 atm and a vanadium(V) oxide catalyst

    11. 6.3.11Typical Haber and Contact process

      • Explain why typical Haber and Contact process conditions are used, considering reaction rate, equilibrium position, safety and economics

  4. 6.4 Redox

    1. • Use a Roman numeral to indicate the oxidation number of an element in a compound

    2. • Define redox reactions as involving simultaneous oxidation and reduction

    3. • Define oxidation as gain of oxygen and reduction as loss of oxygen

    4. • Identify redox reactions as reactions involving gain and loss of oxygen

    5. • Identify oxidation and reduction in redox reactions

    6. • Define oxidation in terms of: (a) loss of electrons (b) an increase in oxidation number

    7. • Define reduction in terms of: (a) gain of electrons (b) a decrease in oxidation number

    8. • Identify redox reactions as reactions involving gain and loss of electrons

    9. • Identify redox using oxidation numbers: (a) uncombined elements are 0 (b) monatomic ion number equals ion charge (c) compound total is 0 (d) ion total equals ion charge

    10. • Identify redox reactions by the colour changes involved when using acidified aqueous potassium manganate(VII) or aqueous potassium iodide

    11. • Define an oxidising agent as a substance that oxidises another substance and is itself reduced

    12. • Define a reducing agent as a substance that reduces another substance and is itself oxidised

    13. • Identify oxidising agents and reducing agents in redox reactions