1.8 Acids, Bases and Salts
Indicators, pH, hydrogen and hydroxide ions, neutralisation, acid reactions, salt preparation and acid strength.
How to study for CCEA GCSE Chemistry
Connect particle models to observations, balance every quantitative relationship, and prepare each prescribed practical from safe method through analysis and evaluation.
Core concepts
Concept 1
Acids produce hydrogen ions in aqueous solution, alkalis produce hydroxide ions, and neutralisation forms water from these ions.
Exam cue: Use the acid name and positive ion source to name the salt.
Concept 2
Acids react in characteristic ways with metals, bases and carbonates, producing predictable salts and other products.
Exam cue: Choose excess solid plus filtration for a soluble salt made from an insoluble base or carbonate.
Concept 3
The salt-preparation method depends on whether the salt and starting material are soluble.
Exam cue: Distinguish acid strength from concentration when interpreting pH or reaction data.
Risk pitfalls and guardrails
Calling every base an alkali even when it is insoluble.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a particle-level explanation with a vague observation.
Using evaporation to dryness where crystallisation is required.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a particle-level explanation with a vague observation.
Saying neutralisation always produces a pH of exactly 7 regardless of reactants and amounts.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a particle-level explanation with a vague observation.
Memory anchors
Acid
A substance producing hydrogen ions in aqueous solution.
Alkali
A soluble base producing hydroxide ions in aqueous solution.
Neutralisation
Hydrogen ions react with hydroxide ions to form water.
Acid plus metal
Salt plus hydrogen, for a sufficiently reactive metal.
Acid plus carbonate
Salt plus water plus carbon dioxide.
Crystallisation
Concentrate a solution, cool to form crystals, then separate and dry them.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Which ion makes an aqueous solution acidic?
Which ion makes an aqueous solution alkaline?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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