Extraction of metals Flashcards
What are ores?
Rocks that contain metal or metal compounds are called ores.
What does the extraction of metal depend on?
The method of extraction of a metal from its ore (metal oxide) depends on its position in the electrochemical series.
Why is it harder to extract some metals from their ores than others?
The more reactive the metal, the more stable its compounds and the harder it is to extract the metal from its ore.
What are all extraction reactions?
All extraction reactions involve the positive metal ions in the compound being changed into metal atoms by gain of electrons and therefore all extraction reactions are examples of reduction.
Which metals are extracted by heating alone?
Metals below copper in the electrochemical series such as silver and mercury are extracted by heating the metal oxide.
Which metals are extracted by heating their compounds with carbon or carbon monoxide?
Metals with low to medium reactivity can be extracted by heating their compounds with carbon or carbon monoxide. These metals occur above mercury and below aluminum in the electrochemical series. The carbon helps remove the oxygen from the metal oxide. The oxygen transfers to the carbon forming carbon dioxide.
How is iron extracted from its ore?
Iron is extracted from its ore in a blast furnace. Haematite is the iron ore Fe2O3. Coke (carbon) is burned in a blast of hot air and at these temperatures reacts to form carbon monoxide. The carbon monoxide gas bubbles up through the hot iron ore, stripping the oxygen off it and reducing the iron metal.
What is haematite?
Haematite is the iron ore Fe2O3.
Why is limestone added to the blast furnace to extract iron?
The limestone helps remove impurities from the ore and these float on top of the iron metal as a molten slag that can be easily removed.
What is the reaction to the extraction of iron in the blast furnace?
Iron (iii) oxide + carbon monoxide → iron + carbon dioxide
Why is carbon monoxide more efficient than carbon at reducing oxide from iron(iii)oxide?
Carbon monoxide is much more efficient than carbon at reducing the oxide as it is a gas and is, therefore, able to have better contact with the ore.
What is electrolysis?
Electrolysis is the splitting of an ionic compound into its elements, using electricity.
Which metals are extracted using electrolysis?
All metals above zinc in the electrochemical series are extracted using electrolysis.
What are the electrodes used in electrolysis made of?
Graphite because it conducts electricity.
What power supply is used in an electrolysis experiment and why?
In an electrolysis experiment a d.c. pwer supply is essential so that the electrodes are oppositely charged and the elements produced can be identified and collected at the electrodes.
