Unit 1: 3 - Metals and their uses Flashcards
What is an ore?
Rock that contains enough metal or a metal compound to make it worth extracting.
What type of metals can be extracted from ores using physical methods (e.g. smelting)?
Unreactive metals (low in the reactivity series, such as gold) as they are found as the pure metal rather than as a compound.
How can metals be extracted from a compound?
By displacement using a more reactive element.
What type of elements can be extracted by heating with carbon? What is this called?
Metals which are less reactive that carbon; this is called reduction.
How is iron (III) oxide extracted from an ore?
In a blast furnace using carbon.
How do reduction reactions work?
The carbon removes the oxygen which is released as carbon oxides (usually CO2).
What percentage of iron is in the iron made from a blast furnace?
About 96%
What is wrong with the iron made from a blast furnace?
The impurities make it brittle so it has few uses.
Give a use for iron from a blast furnace.
Cast iron.
What are steels?
Alloys of iron and other elements, often carbon or metals like chromium.
What main property do low-carbon steels have?
They are easily shaped.
What main property do high-carbon steels have?
They are hard.
What is stainless steel?
Steel that contains larger quantities of other metals, like chromium, which resists corrosion.
Why can aluminium not be reduced using carbon?
Aluminium is more reactive than carbon.
What properties does aluminium have? (2)
Low density and resistant to corrosion (even though it is quite high up in the reactivity series).
How is aluminium extracted?
Using electrolysis.
What is aluminium usually made up into and why?
Alloys, as pure aluminium is not very strong.
What properties does titanium have? (3)
It is very strong, resistant to corrosion and has a low density compared to other strong metals.
What is the problem with extracting titanium from its oxide by reduction?
The metal reacts with the carbon making it brittle.
Why is the extraction of titanium expensive?
It requires several stages and large amounts of energy.
How can copper be extracted from copper-rich ores?
Smelting (physical method, as copper is quite unreactive).
What is the problem with producing copper by physical methods and how do we deal with this?
It produces impure copper, which we then electrolyse.
Why is smelting and purifying copper ore a problem?
It requires large amounts of energy.
What is an increasing problem with copper?
It is a limited and very useful resource, and the amount of copper-rich ores are running out.
