C1.16a Extracting copper Name
Class
Date
You are going to extract copper metal from copper oxide by heating with carbon.
Apparatus
Health and safety
Bunsen burner
charcoal
test-tube holder
ignition tube
copper oxide
mat
cotton wool
tongs
spatula
●
Wear eye protection
●
Copper compounds are harmful
●
Take care with hot apparatus
Method A
Put one spatula full of copper oxide in an ignition tube.
B
Put one spatula full of charcoal in the tube. Do not mix them.
C
Heat the ignition tube in a Bunsen flame for five minutes.
D
Leave the tube to cool down on the bench mat for a few minutes.
E
Tip out the contents of the ignition tube and look for brown-red copper.
copper oxide + carbon
Bunsen burner
Considering your results/conclusions 1
Did you see evidence of copper in your experiment? __________________________________________________________________________________ __________________________________________________________________________________
Evaluation 2
a Why does heating with carbon extract copper from copper oxide? __________________________________________________________________________________
b Write a word equation for this reaction. __________________________________________________________________________________
© Pearson Education 2010. Edexcel GCSE Science Activity Pack This document may have been altered from the original.
C1.16b The history of metals There are currently more than 80 known metals, but most of these have been discovered quite recently. The earliest metals were either those found as elements (the ’native‘ elements) or metals that were extracted very easily from compounds in ores by heating with carbon. Gold was one of the first metals to be discovered, around 6000 BCE. Much of this gold seems to have been used for jewellery such as bracelets and rings, and it was in use by the end of the Stone Age. Silver was discovered shortly afterwards and was also used mainly for jewellery and ornaments. Copper was also one of the first metals to be discovered, possibly by ancient potters whose furnaces were hot enough to produce copper from the ore malachite. By 2500 BCE, it had been discovered that bronze could be made by melting a mixture of copper and tin ores. This led to the Bronze Age. Copper and bronze were used to make tools and weapons. In about 1200 BCE, it was discovered that iron could be made by heating iron ore with charcoal (a form of carbon) to a very high temperature. This led to the start of the Iron Age. Iron has a higher melting point than bronze, so bronze can be melted and cast more easily. However, heating and hammering iron while it is still solid makes it much harder than bronze. Iron ores are also much easier to find than tin, so iron took over from bronze as the main metal in use. Before 1800, only 12 metals were known. In 1799, Alessandro Volta made the first battery, making electricity available for the first time. This led to the extraction and discovery of many new metals. In 1807, Sir Humphrey Davy used a battery to extract potassium and sodium from their molten ores by electrolysis. Soon chemists found out how to use this method to extract other reactive metals such as calcium, magnesium and aluminium. This method was very expensive at first, but over time the batteries used to produce direct current improved, making electrolysis much cheaper. This made these metals more readily available, although electrolysis is still more expensive than heating with carbon because of the cost of electricity. By the end of the 19th century, 41 further pure metal elements had been obtained, with many more being discovered during the 20th century. 1
Explain why metals such as gold and silver are found naturally as elements, whereas most other metals are found in compounds.
2
What were the first three metals to be discovered?
3
What is bronze?
4
How was copper probably first extracted from its ore?
5
a How was iron first extracted from its ore? b Write a word equation for the extraction of iron from the ore iron oxide. c Explain why iron can be extracted in this reaction. d Explain why iron took over from bronze as the most important and used metal.
6
Explain why reactive metals such as aluminium could not have been extracted before the end of the 18th century.
7
Suggest why metals that have a high reactivity are more expensive to extract.
Extra challenge 8
Suggest an equation for the extraction of sodium from sodium chloride by electrolysis.
Š Pearson Education 2010. Edexcel GCSE Science Activity Pack This document may have been altered from the original.