Acids, Bases and Salts

Acids, Bases and Salts

1. pH 7

   • Acids = less than 7
   • Bases = more than 7
     • ALKALIS
   • NEUTRAL CHEMICALS have pH7
     • NOT ACIDS
     • NOT BASES
     • Dont change the colour of Litmus Paper
     • Turn Universal Indicator GREEN
     • WATER
     • Parafin

2. Acids

   • Turn blue litmus paper RED
   • Strong acids turn universal indicator red
   • Weak Acids turn universal indicator hyellow or orange

3. Bases

   • Usually metal oxides or metal hydroxides
     • Copper oxide
     • Sodium Hyrdroxide
   • Not all bases dissolve in water
     • Most do
     • Copper Oxide doesnt
     • Soduim Hydroxide can
   • If a base can dissolve in water, it is an Alkali
     • the stronger the alkali the higher the pH value
     • Turn Red Litmus paper BLUE
     • turn universal indicator blue or purple if they are strong
     • turn universal indicator blue green isa they are weak

4. Salts

   • Compounds
   • Sodium Chloride
     • edible salts
   • Formed by acids reacting with bases, carbonates or metal
   • Acids and Bases
     • Reaction between an acid and a base is called NEUTRALISATION
     • It produces a salt and water
   • Acids and carbonate
     • Forms salts, water and carbon dioxide
     • CO2 causes bubbling during the reaction
     • Limewater turns a cloudy white when carbon dioxide is bubbled through it
   • Acids and Reactive metals
     • Salt and hydrogen gas is formed
       • No water
     • Hydrogen can be detected with a lighted splint and makes a squeaky pop
   • Salt names
     • Two parts, one from the base and one from the acid
     • Sodium Hydroxide + Hydrochloric Acid = Sodium Chloride
       • Sodium comes from the Base
       • Chloride comes from the acid
     • Sulphuric acids make sulphates
     • Nitrate acids = Nitrate
   • Making a salt from an alkaline solution
     • Formed when a base dissolves in water
     • Add acid to the alkali very slowly
       • use universal indiciator to tell when you reach a neutral state
         • IT WILL GO GREEN
     • Makes salt and water

5. Carbonate

   • Chalk
   • Marble
   • Limestone