yr 11 syllabus questions on metal (1 Viewer)

[**freakstar87**]

hey can anyone help me on these chem syllabus questions on metal plz? thanx if you know anything!

1.a) Outline and examine some uses of different metals through history, including contemporary uses as uncombined metals or as alloys

1.b) Describe the use of common alloys including steel, brass and solder and explain how these relate to their properties

1.c) Explain why energy input is necessary to extract a metal from its ore

1.d) Identify why there are more metals available for people to use now than there were 200 years ago

1.e) Gather, process, analyse and present information from secondary sources on the range of alloys produced and the reasons for the production and use of these alloys

1.f) Analyse information to relate the chronology of the Bronze Age, the Iron Age and the modern era and possible future developments.

also, if you know any good chem websites that answers these following questions, feel free to post them here

 

[Heinz]

Copied and pasted from my cheapy old Prelim chem summary (ahh the memories...)

"1.2.1
6000 BC: copper was the first metal used by humans for simple tools

4000 2500 BC: the first annealing of working copper. Copper was first smelted in the Sinai Desert in Israel

3000 2500 BC: Copper was alloyed with tin in southern Europe (90% Cu / 10%Sn). Bronze increased the hardness and was used as weaponry in the Trojan Wars. Zinc ore was also used to make brass (70% Cu / 30% Zn) in Mesopotamia centuries before elemental zinc was even isolated.

1000 BC: The use of bronze weapons rapidly diminished with the onset of the Iron Age because the harder iron weapons were more powerful. Iron merchants helped to end the Bronze Age.

100 BC: Brass was widely used in ancient Rome and in China.

Nowadays, the most common metals in use are iron and aluminium. Iron however, is not used in its pure elemental state, but as an alloy of steel for construction purposes. As aluminium is one of the Earths most abundant metals, it is used for a variety of purposes ranging from saucepans, foil, aircraft and drink cans.

1.2.2
Steel
Carbon steels are mainly used for car bodies, ships, bridges and buildings. Mild steel is used because it is cheap, ductile and easily welded. Steels with higher carbon content are used because it increases the metals hardness.
Stainless steels which are used for sinks and cutlery because they are strong and resistant to corrosion.

Brass alloys are composed of copper and zinc. Because they are harder than elemental copper, brass is used for plumbing fittings, screws, musical instruments and shell cases.

The main types of solders used commercially consist of varying degrees of lead and tin. Since most solders are soft and easily worked due to their low melting points, solders are highly used in conjunction with other metals namely, to seal other metals together.

1.2.3
For nearly all metals a chemical reaction is used to extract the metal from its ore.
Because chemical reactions are accompanied with either the release or absorption of heat, the extraction of most metals therefore, requires considerable of energy. Copper ores such as chalcopyrite and chalcocite are exceptions. However, energy is also required to mine the ore, maintain high temperatures needed for certain reactions to take place and also to purify or concentrate the metal. Therefore, a large amount of energy is needed to extract a metal from its ore.

1.2.4
The use of metals closely parallels their ease of extraction. Therefore, approximately 200 years ago, aluminium for example, was not in use. Limited technology meant that the extraction processes available today, were unavailable to people back then. Such processes included electrolysis and froth flotation. With the process of electrolysis, economic factors also hindered the use of many metals. Compared to yesteryears, the cost of extracting certain metals was much higher than compared to metals such as iron. With the onset of cheaper electricity however, came the use of more and more expensive metals with much more favourable physical properties. Another reason could include the creation of the periodic table in 1869 which left gaps for undiscovered elements."

I can't be bothered finding the answers to the column three dot points since my prelim stuff has been stored in my garage.

 

[tajche]

Heii, just wondeirng where did u find the outcome answers?, or were they given to you by your teacher?