Chapter 3 - Metals And Their Uses Flashcards
(22 cards)
How can metals be extracted from compounds
By displacement using a more reactive element.
How can metals which are less reactive than carbon be extracted from their oxides
By heating them with carbon
What kind of reaction is it if carbon is used to extract metals
Reduction reaction because carbon removed the oxygen from the oxide to produce the metal
Why has cast iron only got a few uses
The impurities make it hard and brittle
Why has pure iron (removing carbon dioxide and impurities) got a few uses
It’s too soft for many uses
What are the properties of low carbon steels
They are easily shaped
What are the properties of high carbon steels
They are hard
What is a useful property of stainless steel
It resists corrosion
What are some properties of aluminium
It has a low density and is resistant to corrosion
How is aluminium extracted
By electrolysis of molten aluminium oxide because aluminium is more reactive than carbon so it’s oxide cannot be reduced using carbon.
Why is aluminium expensive to extract
The process of electrolysis requires high temperatures and a lot of electricity.
What are some properties of titanium
It’s resistant to corrosion and is very strong. It also has a low density compared with other strong metals
How can titanium oxide be reduced by
Carbon but the metal reacts with carbon making it brittle
How can copper be extracted from copper rich ores
By smelting. This means heating the ore strongly in a furnace
What does smelting produce
Impure copper, which can be purified by electrolysis
What are the two ways of extracting copper from low grade ores
- Phytomining- uses plants to absorb copper compounds from the ground. The plants are burned and produce ash from which copper can be extracted
- Bioleaching- uses bacteria to produce solutions containing copper compounds
What properties make transition metals useful materials for making things
They are good conductors of heat and electricity. Many of them are strong but can be bent or hammered into shape
What properties of copper make it useful for making pipes and tanks in water and heating systems.
It’s a very good conductor of heat and does not react with water. It can be bent but it is hard enough to keep its shape. It’s a very good conductor of electricity so it is used to electrical wiring
What are the advantages of recycling
Recycling metals saves the energy needed to extract the metal. Recycling saves resources because less ore needs to be mined. Also less fossil fuels is needed to provide the energy to extract the metal from its ore
What are the benefits of using metals in construction
- They are strong
- They can be bent into shape
- They can be made into flexible wires
- They are good electrical conductors
What are the drawbacks of using metals in construction
- Obtaining metals from ores causes pollution and uses up limited resources
- Metals are more expensive than other materials such as concrete
- Iron and steel can rust
What is an ore
Rock that contains enough of a metal to make it worth extracting the metal
