5: Using Resources Flashcards
What is the term for the corrosion of iron?
Rusting.
What is rusting?
The corrosion of iron. Rust forms on the surface of it.
What is required for rust?
Iron, oxygen and water.
What is the word equation for rust?
Iron + Oxygen + Water —> Hydrated Iron Oxide
What are the three methods of preventing rust?
Casting the iron in something, galvanisation, sacrificial protection.
What can we coat the iron in to prevent rusting?
Paint, oil, grease, plastic, a less or more reactive metal.
How can we apply a metal to coat iron?
Electroplating.
What is galvanisation?
Dipping the iron in steel or zinc.
Why do we galvanise the iron in zinc?
Zinc is more reactive than the iron/steel, so it loses electrons, becoming oxidised instead. Any oxygen or water reacts with the zinc, sacrificing itself.
What is sacrificial protection?
Coating the iron in something, with that thing being worn down/used up over time. Galvanisation is a form of sacrificial protection.
What is bronze?
Copper and tin.
What are the properties of bronze?
Tough, resistant to corrosion.
What is brass?
Copper and zinc.
What are the properties of brass?
Hard, workable. Used for musical instruments.
What are aluminium alloy’s properties?
Light-weight, strong.
What are gold alloys made of?
Gold and typically copper.
What are gold alloys used for?
Jewellery.
What are the properties of high carbon steels?
Strong, brittle.
What are the properties of low carbon steels?
Softer, easier to shape.
What is stainless steel made of?
Iron, chromium, nickel.
What are the properties of stainless steel?
Resistant to corrosion, expensive.
How is low density poly ethene made?
Using high pressures and a trace of oxygen.
What is the structure of low density polyethene?
Polymer chains are randomly branched, cannot pack closely together (hence its lower density).
How is high density polyethene made?
Using a catalyst at 50°C and slightly raised pressure.
What is the structure of high density polyethene?
Made up of straighter chains, can pack more closely together, has a higher softening temperature and is stronger than low density polyethene.
Describe the structure of a thermosetting polymer.
Chains fitted together by strong covalent bonds. Cross links. Don’t melt easily.
What do thermosetting polymers make?
Harder plastics with denser structures.
Describe the structure of a thermosoftening polymer.
Tangled web of polymer chains that are relatively easy to separate. Melts easily when heated. Covalent bonding with intermolecular forces.
What do thermosoftening polymers make?
Softer plastics with less dense structures.
Describe the structure and general properties of glass.
Very disordered. Unreactive, inert and acts as a good insulator.
What are the two types of glass?
Sodalime glass and borosilicate glass.
How is sodalime glass made?
Heating a mix of sand, sodium carbonate and limestone.
What are the properties and uses of sodalime glass?
Lower melting and boiling points, used for drink bottles, spectacle lenses. Good for recycling.
What is borosilicate glass made from?
Sand, borontrioxide.
Describe the properties and uses of borosilicate glass.
Higher melting point, brittle, doesn’t conduct electricity. Used for ovenware, test tubes and beakers.
How are ceramics made?
Shaping wet clay and heating it in a furnace.