3.17: Know that Some Reactions are Reversible and this is Indicated by the Symbol ⇌ in Equations

REVERSIBLE REACTIONS: Reaction that can occur in both directions (reactants can react to form products, and products can react to form initial reactants)

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CHEMICAL EQUATIONS FOR REVERSIBLE REACTIONS:

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When writing chemical equations for reversible reactions, two arrows are used with each having half an arrow head (to indicate reaction can occur in both directions):

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Dehydration of Hydrated Copper (II) Sulfate:

Hydrous Copper (II) Sulfate     ⇌     Anhydrous Copper (II) Sulfate     +     Water

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Thermal Decomposition of Ammonium Chloride:

Ammonium Chloride     ⇌     Ammonia     +     Hydrogen Chloride