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• What is an acid?


  A solution with a pH of less than 7 containing excess hydrogen (H+) ions.
• What color does litmus turn in the presence of an acid?


  Red
• What does the term 'acidic' refer to?


  Containing or having the properties of an acid.
• What is acidity?


  The amount of acid in a solution.
• What is the definition of alkaline?


  Having a pH of more than 7.
• What does alkalinity refer to?


  The amount of alkali in a solution.
• What is an aqueous solution?


  A solution with water as the solvent.
• What is concentration in terms of solutions?


  A measure of how much solute is dissolved in a solvent.
• What units are used to express concentration?


  g dm^-3 or mol dm^-3.
• What is an indicator?


  A substance that changes colour depending on the pH of a solution.
• What does it mean for a substance to be neutral?


  A substance that is neither an acid nor an alkali, with a pH of 7.
• What is the pH scale?


  A numerical scale up to 14 that measures acidity or alkalinity based on H+ and OH- concentrations.
• What is a universal indicator?


  An indicator that produces a range of colours depending on the pH.
• What does 'concentrated' mean in terms of solutions?


  Containing a large amount of solute dissolved in a small volume of solvent.
• What does 'dilute' mean in terms of solutions?


  Containing a small amount of solute dissolved in a large volume of solvent.
• What happens when an acid dissociates in water?


  Acid molecules split into H+ ions and negative ions.
• What is a pH meter?


  An electronic device used to measure the pH of a solution.
• What is a strong acid?


  An acidic solute that dissociates completely into ions when dissolved.
• What is a weak acid?


  An acidic solute that does not dissociate completely into ions when dissolved.
• What is a base?


  Any substance that neutralizes an acid, forming a salt and water.
• What is crystallisation?


  The process of forming crystals.
• What does it mean to filter a mixture?


  To remove or separate a solid from a liquid by passing it through a porous material.
• What does it mean to neutralise a solution?


  To make a solution neither acidic nor alkaline by reacting a base with an acid.
• What is a salt?


  An ionic compound produced by a neutralisation reaction.
• What are state symbols?


  Standard symbols written after chemical formulae to indicate the state of a substance.
• What is an alkali?


  A solution with a pH of more than 7 containing excess hydroxide (OH-) ions.
• What color does litmus turn in the presence of an alkali?


  Blue
• What is a balanced equation?


  A way of writing out what happens in a chemical reaction using symbols to represent the substances involved.
• What is a burette used for?


  To accurately measure the volume of solution added during a titration.
• What is the end-point in a titration?


  When just enough solution has been added to react with all the solution in the flask.
• What is a pipette used for?


  To accurately measure a set volume of a solution.
• What is titration?


  A method used to mix acids and alkalis in the correct proportions to produce salt and water.
• What is effervescence?


  Fizzing or a stream of bubbles produced during a reaction.
• What is a half equation?


  A balanced equation that shows what happens to one substance during a redox reaction.
• What is an ionic equation?


  A balanced equation that only shows the ions that react together, excluding spectator ions.
• What is oxidation?


  A reaction in which a substance gains oxygen or loses electrons.
• What is the reactivity series?


  A list of metals in order of reactivity with the most reactive at the top.
• What is reduction?


  A reaction in which a substance loses oxygen or gains electrons.
• What are spectator ions?


  Ions that do not change during a reaction.
• What is a precipitate?


  An insoluble product formed when solutions of two soluble reactants are mixed.