In terms of metal extraction, what is reduction?
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In terms of metal extraction, what is reduction?
In terms of metal extraction, reduction is the removal / loss of oxygen from a compound / ore.
True or False?
Reactive metals are often found as the uncombined element.
False.
Unreactive metals are often found as the uncombined element.
What is haematite?
Haematite is an iron oxide ore.
Give two examples of unreactive metals that can be mined directly.
Examples of unreactive metals that can be mined directly include:
Gold
Silver
Copper
Platinum
State three common processes for extracting metals from ores.
Three common processes for extracting metals from ores include:
Electrolysis
Blast furnace
Reacting with more reactive material
True or False?
Metals are often chemically combined with other substances forming ores.
True.
Metals are often chemically combined with other substances forming ores.
What is a metal ore?
A metal ore is a rock that contains enough of the metal to make it worthwhile extracting.
What is bauxite?
Bauxite is an aluminium oxide ore.
When can a metal reduce a metal oxide?
A metal can reduce a metal oxide when the metal is more reactive than the metal in the oxide.
Define the reactivity series.
The reactivity series orders metals from most reactive to least reactive.
State the method of extraction for metals above carbon in the reactivity series.
Metals above carbon in the reactivity series are extracted by electrolysis.
True or False?
The most reactive metals are at the bottom of the reactivity series.
False.
The most reactive metals are at the top of the reactivity series.
What determines the extraction method for a metal?
The position of the metal on the reactivity series determines the extraction method.
Which metals must be extracted by electrolysis?
Metals that must be extracted by electrolysis are higher up the reactivity series (above carbon) and include aluminum, sodium, potassium, calcium, lithium and magnesium.
True or False?
Iron is extracted by electrolysis.
False.
Iron is extracted by reduction / in the blast furnace.
What is the extraction method for metals below carbon in the reactivity series?
Metals below carbon in the reactivity series are extracted by heating / reduction with carbon.
Name the metal most commonly extracted in a blast furnace.
The metal most commonly extracted in a blast furnace is iron.
True or False?
The higher a metal is on the reactivity series, the more resistant it is to oxidation.
False.
Metals higher up are less resistant to oxidation than the metals placed lower down which are more resistant to oxidation.
In the extraction of metals by heating with carbon, does the metal undergo an oxidation or reduction reaction?
When extracted by heating with carbon, the metal undergoes a reduction reaction.
Name four types of steel.
Four types of steel are: Mild steel High carbon steel Low alloy steel Stainless steel
Which metal is used to make food cans because it is:
Non-toxic
Resistant to corrosion
Resistant to acidic food stuff
The metal used to make food cans because it is non-toxic and resistant to corrosion / acidic food stuff is aluminium.
True or False?
Aluminium is used for making aircraft, electrical wires and water pipes.
False.
Aluminium is used for making aircraft and electrical wires (overhead cables).
Copper is used for water pipes.
Why is aluminium a better choice than copper for overhead electrical cables?
Aluminium is a better choice than copper for overhead electrical cables because it is:
Lower density (lighter)
Has a higher strength-to-weight ratio
What is the desirable property of high carbon steel for making tools, such as chisels?
The desirable property of high carbon steel for making tools, such as chisels, is its hardness / strength.
Which metal is used for electrical wiring because it is a good conductor of electricity and ductile?
Copper is used for electrical wiring because it is a good conductor of electricity and ductile.
Why are aluminium, copper and stainless steel used to make saucepans?
Aluminium, copper and stainless steel are used to make saucepans because they are:
Good conductors of heat
Resistant to corrosion
True or False?
Stainless steel is used to make knives, forks and spoons because it is resistant to corrosion.
True.
Stainless steel is used to make knives, forks and spoons because it is resistant to corrosion.
What type of steel is used for car bodies and why?
Mild steel is used for car bodies because it is soft and malleable.
What property of copper means that it can be shaped into saucepans?
The property of copper that means it can be shaped into saucepans is malleability.
What is an alloy?
An alloy is a mixture of metals, where the metals are mixed together physically but are not chemically combined.
True or False?
Alloys can be made from metals mixed with non-metals.
True.
Alloys can also be made from metals mixed with non-metals such as carbon.
Describe the structure of an alloy.
Alloys contain atoms of different sizes which distort the regular arrangement of atoms.
What is the cause of increased hardness and strength in alloys?
The increased hardness and strength of an alloy is caused by the different size atoms which distort the regular arrangements of atoms, preventing the layers from sliding over each other easily.
State an advantage of using alloys over pure metals.
An advantage of using alloys over pure metals is that alloys can have:
Greater strength
Greater hardness
Increased resistance to corrosion
Increased resistance to extreme temperatures
True or False?
Alloys are chemically combined mixtures of metals.
False.
Alloys are physical mixtures of metals, where the metals are not chemically combined.
How do properties of alloys differ from pure metals?
Alloys often have greater strength / hardness, or resistance to corrosion / extreme temperatures compared to pure metals.