Chemistry, Unit 1

Chemistry, Unit 1

1. hazard symbols

   • oxidising
     • provides oxygen which allows other materials to burn more fiercely
     • liquid oxygen is an example
   • highly flammable
     • catches fire easily
     • petrol for example
   • harmful
     • not as dangerous as toxic but similar
     • example:copper sulfate
   • toxic
     • can cause death by swallowing, breathing in or absorption
     • hydrogen cyanide
   • irritant
     • can cause reddening or blistering of the skin
   • corrosive
     • attacks and destroys living tissues
     • very concentrated sulfuric acid

2. pH scale

   • when adding universal indicator to an acid, alkali or base, the substance changes these colours.
     • a base is a substance with a PH more than 7
       • an alkali is a base that can be dissolved in water
     • an acid is a substance with pH less than 7
     • an acid and a base react together to form salt and water
       • salts are used in fertilisers and colouring agents within fireworks

3. HCL and indigestion

   • stomach produces HCL
     • enzymes work the best in an acidic environment
     • kills bacteria
   • too much HCL creates indigestion
     • indigestion tablets contain calcium carbonate ( a base)
       • neutralise excess acid

4. metal hydroxides and metal oxides are generally bases therefore they react with an acid to form a salt and water.

   • if it was a metal CARBONATE it would form salt, water and CARBON dioxide when reacted with a acid

5. Electrolysis

   • The splitting up of a liquid compound by using electricity.
     • uses a direct current source ( like a battery)
     • the electrolyte ( the compound we're breaking apart) must be in liquid form in able to conduct the electricity
     • the electricity is applied to the electrolyte by two electrodes- often made of carbon.
   • we can split up HCL into hydrogen and chlorine
     • to test for chlorine it will bleach damp litmus paper white after turning it red
       • chlorine is toxic
         • used to treat water supplies
         • needed for the manufacture of bleach
         • and to create PVC
     • hydrogen makes a squeaky pop sound when lit with a splint

Images and files in the map