6. Chemical reactions
- Syllabus
- 0620–2026–2027
- Section
- 6
- Level
- —
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In this section
Topic 6.1
6.1 Physical and chemical changes
Objectives in this topic
6.1.1—Physical and chemical changes, and
- Identify physical and chemical changes, and describe the differences between them
Topic 6.2
6.2 Rate of reaction
Objectives in this topic
6.2.1—Rate changes caused by concentration
- Describe rate changes caused by concentration, gas pressure, solid surface area, temperature and adding/removing catalysts, including enzymes
6.2.2—Catalyst increases the rate of a
- State: a catalyst increases the rate of a reaction and is unchanged at the end of a reaction
6.2.3—Practical 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
6.2.4—Interpret data
- Interpret data, including graphs, from rate of reaction experiments
6.2.5—Collision 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
6.2.6—Rate changes using collision theory
- Explain rate changes using collision theory for concentration, gas pressure, solid surface area, temperature and adding/removing catalysts, including enzymes
6.2.7—Catalyst decreases the activation
- State: a catalyst decreases the activation energy, Ea, of a reaction
6.2.8—Evaluate 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
Topic 6.3
6.3 Reversible reactions and equilibrium
Objectives in this topic
6.3.1—Some chemical reactions are reversible
- State: some chemical reactions are reversible as shown by the symbol ⇌
6.3.2—Changing 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
6.3.3—Reversible 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
6.3.4—Predict 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
6.3.5—Symbol equation for the production of
- State the symbol equation for the production of ammonia in the Haber process, N2(g) + 3H2(g) ⇌ 2NH3(g)
6.3.6—Sources of the hydrogen (methane) and
- State the sources of the hydrogen (methane) and nitrogen (air) in the Haber process
6.3.7—Typical conditions in the Haber
- State the typical conditions in the Haber process as 450 °C, 20 000 kPa/200 atm and an iron catalyst
6.3.8—Symbol 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)
6.3.9—Sources 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
6.3.10—Typical 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
6.3.11—Typical Haber and Contact process
- Explain why typical Haber and Contact process conditions are used, considering reaction rate, equilibrium position, safety and economics
Topic 6.4
6.4 Redox
Objectives in this topic
6.4.1—Roman numeral to indicate the
- Use a Roman numeral to indicate the oxidation number of an element in a compound
6.4.2—Redox reactions as involving
- Define redox reactions as involving simultaneous oxidation and reduction
6.4.3—Oxidation as gain of oxygen and
- Define oxidation as gain of oxygen and reduction as loss of oxygen
6.4.4—Redox reactions as reactions involving
- Identify redox reactions as reactions involving gain and loss of oxygen
6.4.5—Oxidation and reduction in redox
- Identify oxidation and reduction in redox reactions
6.4.6—Oxidation in terms of: (a) loss of
- Define oxidation in terms of: (a) loss of electrons (b) an increase in oxidation number
6.4.7—Reduction in terms of: (a) gain of
- Define reduction in terms of: (a) gain of electrons (b) a decrease in oxidation number
6.4.8—Redox reactions as reactions involving
- Identify redox reactions as reactions involving gain and loss of electrons
6.4.9—Redox using oxidation numbers: (a)
- 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
6.4.10—Redox reactions by the colour changes
- Identify redox reactions by the colour changes involved when using acidified aqueous potassium manganate(VII) or aqueous potassium iodide
6.4.11—An oxidising agent as a substance that
- Define an oxidising agent as a substance that oxidises another substance and is itself reduced
6.4.12—Reducing agent as a substance that
- Define a reducing agent as a substance that reduces another substance and is itself oxidised
6.4.13—Oxidising agents and reducing agents
- Identify oxidising agents and reducing agents in redox reactions