C1- metals and their uses Flashcards
What is the metal ore?
A metal ore is a rock containing a metal, or a metal compound, in high enough concentration to make it economic to extract the metal.
How are metal ores collected?
Ores are mined. They may need to be concentrated before the metal is extracted and purified. The economics of using a particular ore may change over time. For example, as a metal becomes rarer, an ore may be used when it was previously considered too expensive to mine.
How are metals produced?
Metals are produced when metal oxides are reduced (have their oxygen removed). The reduction method depends on the reactivity of the metal.
Which metals are extracted by electrolysis?
potassium
sodium
calcium
magnesium
aluminium
(all the metals above carbon on the reactivity series)Which metals are extracted by being reacted with carbon and carbon monoxide?
zinc
iron
tin
lead
(all the metals above hydrogen but below carbon)What metals are extracted in various, unspecified ways?
copper
silver
gold
platinum
(all metals below hydrogen)Why does gold not need to be chemically extracted from its ore?
Gold, because it is so unreactive, is found as the native metal and not as a compound. It does not need to be chemically extracted from its ore, but chemical reactions may be needed to remove other elements that might contaminate the metal.
What are the transition metals?
The transition metals are placed in the periodic table in a large block between groups 2 and 3. Most metals (including iron, titanium and copper) are transition metals.
What are the common properties of transition metals?
they are metals
they are good conductors of heat and electricity
they can be hammered or bent into shape easily
Why are transition metals useful?
The transition metals are useful as construction materials. They are also useful for making objects that need to let electricity or heat travel through them easily.
What are reduction reactions?
Reactions in which oxygen is removed
How is iron extracted (2 equations needed)?
Iron is extracted from iron ore in a huge container called a blast furnace. Iron ores such as haematite contain iron oxide.
Carbon is more reactive than iron, so it can push out or displace the iron from iron oxide. Here are the equations for the reaction:
iron oxide + carbon → iron + carbon dioxide
In the blast furnace, it is so hot that carbon monoxide will also reduce iron oxide:
Iron oxide + carbon monoxide → iron + carbon dioxide
Why is copper useful?
Copper is soft and easily bent and so is a good conductor of electricity, which makes it useful for wiring. Copper is also a good conductor of heat and it does not react with water. This makes it useful for plumbing, and making pipes and tanks.
How is copper extracted?
Some copper ores are copper-rich – they have a high concentration of copper compounds. Copper can be extracted from these ores by heating them in a furnace, a process called smelting. The copper is then purified using a process called electrolysis.
How does electrolysis work? (use copper as an example)
Electricity is passed through solutions containing copper compounds, such as copper sulfate. During electrolysis, positively charged copper ions move towards the negative electrode and are deposited as copper metal.
What is the issue with copper?
We are running out of copper-rich ores. Research is being carried out to find new ways to extract copper from the remaining low-grade ores, without harming the environment too much. This research is very important, as traditional mining involves huge open-cast mines that produce a lot of waste rock.
What is phytomining?
Some plants absorb copper compounds through their roots. They concentrate these compounds as a result of this. The plants can be burned to produce an ash that contains the copper compounds. This method of extraction is called phytomining.
What is bioleaching?
Some bacteria absorb copper compounds. They then produce solutions called leachates, which contain copper compounds. This method of extraction is called bioleaching.
How can copper be produced from solutions of copper salt?
Copper can also be extracted from solutions of copper salts using scrap iron. Iron is more reactive than copper, so it can displace copper from copper salts. For example:
iron + copper sulfate → iron sulfate + copper
Why is Aluminium and titanium useful?
Aluminium and titanium are two metals with a low density. This means that they are lightweight for their size. They also have a very thin layer of their oxides on the surface, which stops air and water getting to the metal, so aluminium and titanium resist corrosion.
What is aluminium used for?
Aluminium is used for aircraft, trains, overhead power cables, saucepans and cooking foil.
What is titanium used for?
Titanium is used for fighter aircraft, artificial hip joints and pipes in nuclear power stations.
What is the issue with the extraction of aluminium and titanium?
Unlike iron, aluminium and titanium cannot be extracted from their oxides by reduction with carbon. Existing methods are expensive because:
the processes have many stages
large amounts of energy are needed
Why is aluminium often recycled and what is the advantage of this?
Aluminium is extensively recycled because less energy is needed to produce recycled aluminium than to extract aluminium from its ore. Recycling preserves limited resources and requires less energy, so it causes less damage to the environment.
What are alloys?
A mixture of two or more elements, where at least one element is a metal
Why are alloys harder than pure metals?
Alloys contain atoms of different sizes, which distort the regular arrangements of atoms. This makes it more difficult for the layers to slide over each other, so alloys are harder than the pure metal.
What does brass contain and what is it used for?
brass, used in electrical fittings, is 70 percent copper and 30 percent zinc
What does 18 carat gold contain and what is it used for?
18 carat gold, used in jewellery, is 75 percent gold and 25 percent copper and other metals
What is duralumin used for and what does it contain?
duralumin, used in aircraft manufacture, is 96 percent aluminium and 4 percent copper and other metals.
Why is pure iron soft?
ure iron is soft and easily shaped because its atoms are arranged in a regular way that lets layers of atoms slide over each other.
Why is most iron from the blast furnace converted into steel?
Iron from the blast furnace is an alloy of about 96 percent iron, with carbon and some other impurities. It is hard, but too brittle for most uses
How is steel formed?
Carbon is removed from molten iron by blowing oxygen into it. The oxygen reacts with the carbon, producing carbon monoxide and carbon dioxide, which escape from the molten metal. Enough oxygen is used to achieve steel with the desired carbon content. Other metals are often added, such as vanadium and chromium, to produce alloys with properties suited to specific uses.
What is low-carbon steel alloyed with, and what are its properties and uses?
about 0.25 percent carbon, it is easily shaped and is used for car body panels
What is high-carbon steel alloyed with, and what are its properties and uses?
up to 2.5 percent carbon,hard, used for cutting tools
What is stainless steel alloyed with, and what are its properties and uses?
chromium and nickel, resistant to corrosion, used in cutlery and sinks
