Introduction to reversible chemical reactions
I can describe reversible chemical reactions, represent them using chemical equations, and give examples.
Introduction to reversible chemical reactions
I can describe reversible chemical reactions, represent them using chemical equations, and give examples.
Lesson details
Key learning points
- Different types of arrows (→, ⇌) are used in chemical equations to indicate the nature of the reaction.
- Reversible reactions are symbolised using the double-headed arrow (⇌) in chemical equations.
- In a reversible reaction, both the forward and reverse reactions can occur under the right conditions.
- hydrated copper sulfate (blue) ⇌ anhydrous copper sulfate (white) + water
- ammonium chloride ⇌ ammonia + hydrogen chloride
Common misconception
Students often think that a reversible reaction will always go to completion in one direction before reversing.
Explain that in a reversible reaction, if the conditions allow it, both the forward and backward reaction can occur at the same time.
Keywords
Reversible reaction - A chemical reaction where the reactants form products that, in turn, react together to reform the reactants.
Hydrated (salt) - A salt that contains water molecules within its crystal structure, shown by a dot in its formula, e.g. hydrated copper(II) sulfate (CuSO₄·5H₂O).
Anhydrous (salt) - A salt that does not contain any water molecules in the crystal structure, e.g. anhydrous copper(II) sulfate (CuSO₄).
Double-headed arrow (⇌) - Used to show that a chemical reaction is reversible.
Single-headed arrow (→) - Used to show the direction of an (irreversible) chemical reaction, showing that reactants form products.
Equipment
Test tubes, clamp and stand, ammonium chloride, hydrated copper(II) sulfate, Bunsen burners, mineral wool, delivery tube and bung, ice bath.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
energy is transferred from the surroundings to the reaction
energy is transferred from the reaction to the surroundings
Exit quiz
6 Questions
reactants form products, and the reaction goes to completion
both forward and backward reactions occur under the correct conditions
contains water molecules in its crystal structure (dot in the formula)
does not contain any water molecules in the crystal structure