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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. 6.2.1Rate changes caused by concentration

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

    2. 6.2.2Catalyst increases the rate of a

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

    3. 6.2.3Practical methods for investigating

      • 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. 6.2.4Interpret data

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

    5. 6.2.5Collision theory in terms of: (a)

      • 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. 6.2.6Rate changes using collision theory

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

    7. 6.2.7Catalyst decreases the activation

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

    8. 6.2.8Evaluate practical methods for

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

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

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

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

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

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

    10. • 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. • 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