C1.3 Metals and their uses

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Where are metals generally found?
In the Earth's crust
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Why do metals have to be chemically separated before they can be used?
They are mainly found chemically combined with other elements (often oxygen)
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What is an ore?
A rock with enough metal in it to make it financially worth extracting
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What are the 4 stages copper ore must go through to extract the pure copper?
Ground into a powder --> Mixed with water + a chemical which makes it repel water --> Air bubbled through mixture --> Copper floats to the top
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What 2 things determine whether it's worth extracting a metal?
Amount of metal and easiness of extraction
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What is the reactivity series?
Comparison of reactivity of different elements
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What happens if a more reactive metal reacts with an ore containing a less reactive metal?
The more reactive one displaces the other; it is a way of extracting less reactive metals
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What has to be done to cause carbon to replace a metal oxide?
Heat them
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What type of reaction is the removal of oxygen from a compound?
Chemical reduction
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How are metals more reactive than carbon extracted from their ores?
Electrolysis
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What is cast iron and its properties?
Iron straight from the blast furnace - it contains impurities (mainly carbon) and is very brittle
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What is an alloy?
A metal mixed with (tiny amounts of) other elements
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What are the differences between low- and high-carbon steels?
Low-carbon steel is soft, easily shaped and less likely to break, whereas high-carbon steel is very strong but brittle
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Which 2 metals are both strong and have a low-density?
Aluminum & titanium
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How are titanium/aluminum non-corrosive despite being fairly high in the reactivity series?
The atoms at its surface react with oxygen in the air, forming a thin aluminum oxide barrier
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Briefly describe the process of electrolysis:
Electric current is is passed through a molten ore at high temperatures to break it down
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What are the 4 stages of producing aluminum from its ore?
Mine --> Separate aluminum oxide from its impurities --> Melt it --> Electrolysis
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What is the melting point of titanium?
1660 degrees C (HIGH)
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Why is carbon not used to extract titanium from its oxide?
Carbon reacts with titanium & it becomes brittle
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How is titanium extracted and why is this a problem?
Displaced by sodium/magnesium - both must be extracted by electrolysis first
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What must happen before titanium can be displaced from its ore?
Titanium ore must be separated and converted into a chloride, which is then distilled and purified
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What 2 methods are used to extract copper from its ore?
1. Reacted with sulfuric acid to produce copper sulfate solution; 2. Smelting (heating copper strongly in a furnace)
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Why do scientists need to find new ways of extracting ores?
To get copper from low-grade ores (high-grade ones are running out)
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Give 2 examples of a new method of extracting copper:
Phytomining (plants absorb copper ions as they grow, then they're burnt so the metal can be leached (dissolved) from ash), or Bioleaching
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What are the 4 general properties of the transition metals?
Good conductors of heat/electricity; Strong; Malleable; Ductile - This makes them very useful
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Give 5 environmental issues associated with exploiting metal ores:
Landscape scarring pits; Noise; Dust; Habitats destroyed; Large heaps of waste rock
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Extracting metal ores can cause ........ and uses up the Earth's .......
Extracting metal ores can cause POLLUTION and uses up the Earth's RESOURCES
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Other cards in this set

Card 2

Front

Why do metals have to be chemically separated before they can be used?

Back

They are mainly found chemically combined with other elements (often oxygen)

Card 3

Front

What is an ore?

Back

Preview of the front of card 3

Card 4

Front

What are the 4 stages copper ore must go through to extract the pure copper?

Back

Preview of the front of card 4

Card 5

Front

What 2 things determine whether it's worth extracting a metal?

Back

Preview of the front of card 5
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