Specification Point 3.17:
Know that some reactions are reversible and this is indicated by the symbol ⇌ in equations
Reversible reactions: A reaction that can occur in both directions (the products can react to produce the original reactants again).
Chemical equations for reversible reactions:
When writing chemical equations for reversible reactions, two arrows are used, each with just half an arrowhead – the top one point right, and the bottom one pointing left:
Dehydration of Hydrated Copper (II) Sulfate:
Hydrous Copper (II) Sulfate ⇌ Anhydrous Copper (II) Sulfate + Water
Thermal Decomposition of Ammonium Chloride:
Ammonium Chloride ⇌ Ammonia + Hydrogen Chloride
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Jamie got a First class degree in Chemistry from Oxford University before going on to teach chemistry full time as a professional tutor. He’s put together these handy revision notes to match the Edexcel IGCSE Chemistry specification so you can learn exactly what you need to know for your exams.
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