Wednesday, May 16, 2012

Blog 11.1 Table J and the Activity Series of Metals [Due Wed May 23rd]

Blog Questions:
1.      The solutions you used were all nitrate solutions. For example, the silver ion solution (Ag1+) is really a solution of silver nitrate (AgNO3). The complete REDOX equation for the reaction between magnesium metal and silver solution is as follows:
         
              Mg(s)    +    AgNO3(aq)     -->    Mg(NO3)2(aq)   +    Ag(s)



a) The nitrate ion is known as a “spectator ion”.  Explain why you think this name is appropriate:

b) In the reaction between magnesium and silver solution, what is oxidized

What is reduced?  


2. Propose a rule that predicts whether or not metal X and metal ion Y+2 will react, based on Table J.

3.  Answer the two “lab questions” from page 1 of this lab:
1.    What is an “ACTIVity series” and how does it relate to what I already know about the behavior of metallic and non-metallic elements?
2.   How is an activity series used to predict (or explain) which metal (or non-metal) is more reACTIVE than another?

4. History of Metals
Currently there are 86 known metals. Before the 19th century only 24 of these metals had been discovered and, of these 24 metals, 12 were discovered in the 18th century. Therefore, from the discovery of the first metals, gold and copper, until the end of the 17th century, some 7700 years, and only 12 metals were known. Four of these metals, arsenic, antimony, zinc and bismuth, were discovered in the thirteenth and fourteenth centuries, while platinum was discovered in the 16th century. The other seven metals, known as the “Metals of Antiquity,” were the metals upon which civilization was based. The first 4 had been discovered and were in use before cultures had developed the ability to communicate in writing.  They are referred to in the oldest written documents we can find (like the book of Genesis in the Bible, as well as ancient Egyptian, Phoenician and Babylonian texts).  These seven metals were:
1.     Gold, 6,000 BC
2.     Copper, 4,200 BC
3.     Silver, 4,000 BC
4.     Lead, 3,500 BC
5.     Tin, 1,750 BC
6.     Iron, 1,500 BC
7.     Mercury, 750 BC

On Table J, the elements above H2 are prone to oxidation in the air, and are therefore unlikely to be found in pure form on the Earth’s surface.  Rather, they are in compounds called “ores” which are metal oxides, like Fe2O3 (iron ore).  Why do you think gold, silver and copper were discovered so long ago by humans, but the other 4 metals were discovered later?

 
A significant advance in human civilization occurred when humans discovered how to extract copper from copper ore.  When mixed with tin, the alloy is called bronze and is harder than either metal separately.  Go to this website.  Check out two things:
·         How copper was “smelted” in ancient times.
·         How bronze was made.

 
Enrichment:
Ag1+ is a very important ion in the history of Rochester, since it was the primary ingredient in George Eastman’s black and white KODAK film industry.  Research how this ion is used in photography.

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