Topic 4 - Obtaining And Using Metals Flashcards
What are unreactive metals found as?
Unreactive metals are found in the earth as uncombined elements
Where are most metals found?
Ores found in the earth’s crust
How are metals extracted from their ores?
Less reactive than carbon - extracted by heating with carbon
More reactive - extracted using electrolysis
What is oxidation? Reduction?
O - gain of oxygen
R - loss of oxygen
Why is the method of extracting a metal from its ore different depending on how reactive it is and the cost of extraction?
Only metals less reactive than carbon can be extracted by a reduction reaction with carbon because more reactive elements form compounds more readily. Aka carbon can only take oxygen away from metals which are less reactive than itself. Electrolysis is v expensive so is only used if the metal cannot be extracted using reduction with carbon.
Describe the electrolysis of aluminium?
The main ore of aluminium is bauxite which contains aluminium oxide. The aluminium oxide is melted and used as the electrolyte for aluminium extraction. Electrolysis decomposes the aluminium oxide into aluminium and oxygen atoms. The aluminium atoms sink to the bottom of the tank as molten aluminium metal.
What are three typical properties of metals?
They’re strong
They’re great at conducting heat
They conduct electricity well
What are aluminium’s properties? What are its uses?
Low density Corrosion resistant Forms hard strong alloys Very useful structural material E.g. Window frames, aircraft, electricity cables
What are copper’s properties? What are its uses?
Hard Strong High melting point Good conductor of electricity E.g. Pipes, doesn't react with water so good for plumbing
What are gold’s properties? What are its uses?
Shiny
Easy to shape
E.g. Jewellery, need for unreactive metals like tooth fillings and electric circuits
What does oxidation of metals result in?
Corrosion
Why are metals that are higher in the reactivity more likely to corrode?
Because they react more easily with oxygen
Give 4 advantages of recycling metals
Uses less raw materials
Saves money
Recycling uses less energy than mining and extracting metals
It makes less rubbish, less landfill
What is an alloy?
An alloy is a mixture of two or more metals, or a mixture of a metal and a non metal.
Why is iron alloyed?
Iron is changed into alloys called steels. Steels are formed by adding small amounts of carbon and sometimes other metals to the iron. The allows produced are stronger and more corrosion resistant.
