Acids and Bases

• What numbers does the pH scale go to and from?

  0 to 14
• What pH does a neutral substance have?

  pH 7
• If a substance is acidic is it on the lower or higher end of the pH scale?

  Lower
• If a substance is alkaline is it on the lower or higher end of the pH scale?

  Higher
• What is an indicator?

  A dye which changes colour depending on whether it's above or below a certain pH
• What is the name for an indicator which contains a mixture of dyes so that it changes colour gradually?

  A wide range indicator
• What is an example of a wide range indicator?

  Universal indicator
• What machine can be used to measure pH?

  A pH probe attached to a pH meter
• Is an electrical method more or less accurate than an indicator for measuring pH and why?

  An electrical method because it gives a numerical value
• What substance neutralises an acid?

  A base
• What is an acid?

  A substance that forms aqueous solutions with a pH under 7
• What ions do acids form in water?

  H+ ions
• What is a base?

  A substance which pH higher than 7
• What is an alkali?

  A base that dissolves into water to form a solution with a pH higher than 7
• What ions do alkalis form in water?

  OH- ions
• What is the word equation for reactions of acids and bases?

  Acid + Base --> Salt + Water
• What is the name for a reaction between acids and bases?

  A neutralisation reaction
• What is the symbol equation for a neutralisation reaction between ions formed by acids and alkalis?

  H+ + OH- --> H2O
• What is the pH of products formed by neutralisation reactions?

  pH 7
• What property of acids and alkalis can be calculated by using neutralisation reactions through titrations?

  Concentration