Topic 5 - Separate Chemistry 1 Flashcards
Transition metal
One of the elements in Groups 3 through 12 of the periodic table whihc forms brightly coloured compounds
Typical transition metal properties (4)
- high melting points, high densities, form coloured compounds, they (and their compounds) can act as catalysts
Corrosion
the deterioration of a metal due to a chemical reaction or oxidisation in the environment
Metal + oxygen…
Metal oxide
Rusting
Where iron or an iron compounds reacts with oxygen and water
Rusting equation
Iron + oxygen + water -> hydrated iron(III) oxide
Rusting experiment
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)
Ways to prevent rusting (5)
painting, electroplating, greasing, sacrificial protection, galvanising
Electroplating and rusting (4)
- 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.
Sacrificial protection (3)
- 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
Galvanising
Applying a thin layer of zinc to a surface of iron or steel for sacrificial protection to take place
Alloy
A mix of two or more elements, where at least one is a metal
Why does alloying make a metal stronger?
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
Mild steel uses, properties and elements
Car body parts, malleable and ductile, carbon and iron
Tool steel uses, properties and elements
Drill bits, hard and high melting point, tungsten, molybdenum and iron
Stainless steel uses, properties and elements
Appliances and work surfaces, hard and rust resistant, chromium and iron
Aluminium vs magnalium (magnesium and aluminium alloy)
Magnalium has a slightly higher density but is stronger. Used to make aircraft parts.
Aluminium properties (5)
- corrosion resistant, good conductor, cheap, strong, low density
Copper vs brass (2)
Cooper is a better conductor, so used in electrical wiring. Brass is stronger, so used for pins in electrical plugs.
Gold vs gold copper alloy
Gold-copper alloy is stronger while still shiny and quite unreactive
chemical cells
Cells contain chemicals which react to produce electricity
Fuel cells
an electrochemical cell that uses replenishable substances such as hydrogen or oxygen or water to produce electricity