Topic 5 - Separate Chemistry 1

One of the elements in Groups 3 through 12 of the periodic table whihc forms brightly coloured compounds

• high melting points, high densities, form coloured compounds, they (and their compounds) can act as catalysts

the deterioration of a metal due to a chemical reaction or oxidisation in the environment

Metal oxide

Where iron or an iron compounds reacts with oxygen and water

Iron + oxygen + water -> hydrated iron(III) oxide

One nail in boiling tube with air and water (both), one with boiled water and a thin layer of oil on surface (no oxygen) and one with just calcium chloride (no water)

painting, electroplating, greasing, sacrificial protection, galvanising

• A thin layer of one metal covers another to increase corrosion resistance. The cathode is the object to be plated. The anode is plating metal. The electrolyte contains ions of the plating metal.

• Process where a metal is connected to a more reactive metal in order to increase corrosion resistance. As the metal to be protected is oxidised, the more reactive metal donates electrons to it. The metal to be protected does not corrode, as it is oxidised and reduced at the same rate

Applying a thin layer of zinc to a surface of iron or steel for sacrificial protection to take place

A mix of two or more elements, where at least one is a metal

Mixing metal atoms of different sizes distorts the regular lattice structure, making it harder for layers to move past each other, making the metal stronger

Car body parts, malleable and ductile, carbon and iron

Drill bits, hard and high melting point, tungsten, molybdenum and iron

Appliances and work surfaces, hard and rust resistant, chromium and iron

Magnalium has a slightly higher density but is stronger. Used to make aircraft parts.

• corrosion resistant, good conductor, cheap, strong, low density

Cooper is a better conductor, so used in electrical wiring. Brass is stronger, so used for pins in electrical plugs.

Gold-copper alloy is stronger while still shiny and quite unreactive

Cells contain chemicals which react to produce electricity

an electrochemical cell that uses replenishable substances such as hydrogen or oxygen or water to produce electricity

Chemical cells ‘go flat’ when one reactant is used up. Fuel cells produce a voltage continuously as long as they have a fuel and oxygen.

• two different metals, each dipped into a solution of one of their salts. A salt bridge made from a saturated solution, usually potassium nitrate to allow ions to pass between