Chapter 7

• 4 ways to prevent rust

  paint.

  oil/ grease.

  galvanisation.

  electroplating
• Paint

  Easy and cheap
• Oil/ grease

  Needs to be redone from time to time
• Galvanisation

  Iron or steel is covered with a thin layer of zinc
• Electroplating

  A thin layer of metal ( chromium or zinc ) attached to the surface of the metal by electrolysis
• Positive test for oxygen gas

  A glowing splint is brought into contact with the gas, if the gas is oxygen the splint will reignite oxygen support combustion but does not burn itself
• Rust

  A slow chemical reaction of the iron metal with oxygen and water which forms iron oxide
• Combustion

  The process of burning something when oxidation takes place quickly at high temperatures
• Oxidation

  When oxygen reacts with other elements and an oxide can form
• Metals with oxygen- what happens to some of the chemical potential energy

  It’s converted into heat and light energy, metal oxides are solid