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Reversible reactions and dynamic equilibrium
Study Reversible reactions and dynamic equilibrium as part of The rate and extent of chemical change for AQA GCSE Chemistry 8462. This topic hub pulls together approved learning objectives, flashcards, MCQs, exam-style questions, answer explanations, revision notes, key terms, common mistakes, exam tips, and mini practice tests where they are published. Use the overview first to understand the curriculum structure, then move into the practice tools to test recall, apply ideas, and check explanations against the specification wording. When revising Reversible reactions and dynamic equilibrium, keep answers specific to the subtopic and use the linked objective pages to separate nearby Chemistry concepts before attempting questions.
43
Objectives
221
Flashcards
221
Questions
90 min
Study time
AQAGCSEChemistryThe rate and extent of chemical change
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Syllabus checklist
What you need to know
43 objective pages available
Reversible reactions7 objectives
- Define a reversible reaction as a reaction in which products can react to make the original reactants.
- Identify the forward reaction and reverse reaction in a reversible reaction.
- Use the reversible reaction symbol in equations.
- Describe examples of reversible reactions such as hydrated copper sulfate and anhydrous copper sulfate.
- Describe thermal decomposition of ammonium chloride as a reversible reaction example.
- Explain that changing conditions can change the direction favoured in a reversible reaction.
- Interpret word and symbol equations for reversible reactions.
Energy changes and reversible reactions6 objectives
- Explain that if one direction of a reversible reaction is exothermic, the opposite direction is endothermic.
- Explain that the same amount of energy is transferred in opposite directions for forward and reverse reactions.
- Identify whether the forward or reverse reaction is exothermic from given information.
- Identify whether the forward or reverse reaction is endothermic from given information.
- Apply energy-change reasoning to reversible reactions such as hydrated copper sulfate.
- Distinguish energy change in a reversible reaction from reaction rate.
Equilibrium7 objectives
- Explain that reversible reactions can reach equilibrium in a closed system.
- Define dynamic equilibrium as the state where forward and reverse reactions continue at the same rate.
- State that concentrations of reactants and products remain constant at equilibrium.
- Explain why equilibrium does not mean reactions have stopped.
- Distinguish closed systems from open systems for equilibrium.
- Use graphs or descriptions to identify when equilibrium has been reached.
- Compare forward and reverse rates before and at equilibrium.
The effect of changing conditions on equilibrium (HT only)5 objectives
- (HT only) State Le Chatelier's Principle as the idea that a system at equilibrium responds to oppose an imposed change.
- (HT only) Explain that changing concentration, temperature or pressure can change the position of equilibrium.
- (HT only) Predict the direction of equilibrium shift from a stated change in conditions.
- (HT only) Distinguish equilibrium shift from reaction rate change.
- (HT only) Explain why a closed system is required when applying equilibrium predictions.
The effect of changing concentration (HT only)6 objectives
- (HT only) Predict that increasing reactant concentration shifts equilibrium towards products.
- (HT only) Predict that decreasing reactant concentration shifts equilibrium towards reactants.
- (HT only) Predict that increasing product concentration shifts equilibrium towards reactants.
- (HT only) Predict that decreasing product concentration shifts equilibrium towards products.
- (HT only) Explain concentration effects using Le Chatelier's Principle.
- (HT only) Interpret concentration changes in industrial equilibrium examples.
The effect of temperature changes on equilibrium (HT only)6 objectives
- (HT only) Predict that increasing temperature favours the endothermic direction of a reversible reaction.
- (HT only) Predict that decreasing temperature favours the exothermic direction of a reversible reaction.
- (HT only) Explain temperature effects on equilibrium using Le Chatelier's Principle.
- (HT only) Use information about the exothermic or endothermic direction to predict product yield.
- (HT only) Distinguish temperature effects on equilibrium position from temperature effects on reaction rate.
- (HT only) Evaluate temperature choices for equilibrium reactions from yield and rate information.
The effect of pressure changes on equilibrium (HT only)6 objectives
- (HT only) Predict that increasing pressure favours the side of a gaseous equilibrium with fewer molecules of gas.
- (HT only) Predict that decreasing pressure favours the side of a gaseous equilibrium with more molecules of gas.
- (HT only) Explain pressure effects on equilibrium using Le Chatelier's Principle.
- (HT only) Count gaseous molecules on each side of an equilibrium equation.
- (HT only) Predict that pressure has no effect on equilibrium position when both sides have the same number of gas molecules.
- (HT only) Evaluate pressure choices for equilibrium reactions from yield, rate and operating cost information.
Key terms
reversible reactiondynamic equilibriumForward reactionReverse reactionreversible reaction symbolhydrated copper sulfateReversible reactionThermal decompositionequilibriumexothermic reactionendothermic reactionreverse reaction
Exam tips
- Understand Reversible Reactions: Use clearly define reversible reactions in your own words, emphasizing that products can reform the original reactants.
- Understand Forward and Reverse Reactions: Use practice identifying the forward and reverse reactions in various reversible reaction equations.
Common mistakes
- Misunderstanding Reversible Reactions: To fix this, students should remember that in a reversible reaction, the products can react to regenerate the reactants, illustrating the dynamic nature of these reactions.
- Confusing Forward and Reverse Reactions: To fix this, carefully analyze the reaction equation and identify the direction of the reactants to products as the forward reaction, and products back to reactants as the reverse reaction.
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