UNIT 7: Acids, bases and salts

• Some acids react with metals to produce what ?

  Metal + acid —-> salt + hydrogen
• What is a redox reaction?

  When oxidation and reduction happen at the same time
• What are acids neutralised by?

  alkalis and bases
• What happens when Acid + metal carbonate ?

  Salts, water and carbon dioxide
• What happens when acid + metal oxide ?

  Salt + water
• What happens when acid + alkali ?

  -neutralisation , produces water and a salt

  -hydrogen from acid reacts with hydroxide from alkali

  -H+ + OH- ——-> H2O
• What is the symbol for hydrochloric acid ?

  HCl
• What is the symbol for sulphuric acid ?

  H2SO4
• What is the symbol for nitric acid ?

  HNO3
• What is the symbol for potassium hydroxide ?

  KOH
• What is the symbol for Ethanoic acid ?

  CH3COOH
• Ammonium


  NH4+
• Nitrate


  NO3-
• Sulfate


  SO4 2-
• Carbonate


  CO3 2-
• Hydrogen carbonate


  HCO3-
• Hydroxide


  OH-
• Hydrogen


  H +
• What happens during a neutralisation reaction ?

  the positive hydrogen ions from the acid react with the negative hydroxide ions from the alkali to form molecules of water.
• How can soluble salts be made ?

  by reacting acids with insoluble bases such as metal oxides, metal hydroxides and metal carbonates
• Salts can be what to form solid salts ?

  Crystallised
• What are the 2 steps of crystallisation ?

  Step 1: obtain solution of the soluble salt that we want

  Step 2: Isolate the soluble salt crystals from the solution
• What is the process of crystallising to get soluble salts ?

  1. With the dilute acid in the heat gently

  2. whilst adding the solid base bit by bit till it stops reacting (it's an excess)

  3. Isolate the salt solution by filtering out the excess solid base using filter paper and a funnel.

  4. Heat salt solution gently in a water bath until crystals form.

  5. Let the solution cool and filter out the soluble salts crystals using filter paper in a funnel
• Acids produce what?


  H+ ions (hydrogen)
• Aqueous solutions of alkalis contain ?

  Hydroxide ions (OH-)
• What is the pH scale?

  A measure of the acidity or alkalinity of a solution
• How can pH be measured?

  Using universal indicator or a pH probe
• What does it mean if solution is 7 ?

  Neutral
• What happens in a neutralisation reaction between an acid and alkali ?

  hydrogen ions react with hydroxide ions to produce water
• What is the symbol equation of a neutralisation reaction ?

  H+(aq) + OH- (aq) —> H2O (I)
• What is concentration measured in ?

  g/dm3
• What is mass using concentration equation ?

  Mass = concentration x volume
• How do you work out concentration ?

  mass/volume
• How do you convert cm3 to dm3 ?

  divide by 1000
• What is a strong acid?

  An acid that is completely ionised in aqueous solution
• What are examples of strong acids?

  hydrochloric acid, sulfuric acid, nitric acid
• What is a weak acid?

  An acid that is only partially ionised in aqueous solution
• What are examples of weak acids?

  Ethanoic, citric and carbonic acids
• Is the acid is strong what is the pH ?


  Lower
• What happens when the pH decrease by one unit?

  The hydrogen ion concentration of the solution increase by a factor of 10