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The subject of this lesson is living in it ownBut people love to have it, andThey destroy own futureOnly to be a master of it. What is it?…
Let’s find a topic of the lesson guessing a
riddle!
?
2
«GOLD»
Au3
Topic of the lesson:
Identify the place of Gold in Mendeleev’s
periodic table
What we will learn from today’s lesson?
Determine physical
property of the gold
Introduce with dissolving process of
gold in aqua regia
Introduce with gold deposit, methods of gold mining and
assess current state of environmental pollution due
to gold mining
Learn how to deal in your living environment from the perspectives of what you learn from ESD programme, build up own responsibility to create safe environment for your and others living, create healthy environment for yourself and others.
Please identify where is the gold in chemical periodic system.
Place in periodic system
Group I• It belongs to clock D, 6th period
and group I• It is 79th element in periodic
system of chemical elements• Its standard atomic weight is
196,967• Its oxidation state are +1 and + 3• Its valency is I , III• Its electron configuration can
written as following: 1s22s22p63s23p63d104s24p64d104f14
5s25p65d106s1
Physical properties
• Gold has bright yellow color• It is most malleable metal and can be beaten
up to 0,0002mm thin.• It is melt in 106,3С • Its density is 19,3gr/cm3
• It is not oxidize in air
The chemical formula of gold dissolving process in aqua regia
2Au + 6HCl+ 2HNO3 = 2AuCI3 +2 NO + 4H2O
What is AQUA REGIA?
•3 HCl: HNO3 3 volumes of Hydrochloric acid : 1 volume of Nitric acid
10
Please write down the chemical formula of nitric acid compounding Aqua regia
electron configuration
:O :H :O: N :
:O
Structural configuration
O // H ─ O ─ N \\
O
Molecular configuration
HNO3
11
Please write down the chemical formula of hydrocloric acid compounding Aqua regia
Electron configuration
H :CI
Structural configuration
H ─ CI
Molecular configuration
HCI
.RANGE OF METALS BY THEIR ACTIVE REACTIONS
Active metals Inactive metals
• The purity of metal measured by millesimal fineness
• It is measured as parts per thousand of pure metal by mass in the alloy
• For example:– 97,5% silver is denoted as “975“– 75% gold is denoted as “750”
Worth to know
As exchange45%
For medals and awards2%
For coin making
19%
In juwellery14%
In elec-
tronics8%
For plat-ing teeth
6%
For plating7%
Rate of gold use in USA and some European countries, in percentage
To the history of gold use
• Human-being from the beginning knew the value of gold and rushed for gold.
• The history of wars and political battles mainly related to willingness of people to have be a master of all gold treasures of the world.
• As result many people even nations died because of high interest in gold. Lot’s of blood slaughtered just only one thing and it is gold
• Even now we can see how many people abandon their life and well-being just to find out a piece of gold.
Au use
Where the gold can be found?
Question 1
• Who are “ninja”-s or artesian miners? • What is an impact of gold mining? Are there
any examples?• Do you know what is a use of mercury?
Let’s discuss Mongolian mining and its impact
Possible solutions to reverse negative impact of gold mining
Solution Advantage Risk
Stop artesian miners The impact of illegal mining, especially application of inappropriate mining practices will be stopped
People involved in illegal mining will operate in more hidden manner
Develop new technology for gold mining
Creates possibilities to decrease negative impact of gold mining
Developing new technology needs time and resources
Enforce technological procedures during the gold mining, implement rehabilitation activities after mining
It is possible to implement due to some promising technologies are already exist and the legislations put in force
Law enforcement in Mongolia is terrible, therefore it might not be implemented.
Your solution? ........................ ....................................
Test1. What is gold number in periodic system?А. 109 Б. 79 В. 472. Which group belongs gold, silver, copper? А. I A b. II A c. I B d. II B3. How many base acids compounds Aqua regia?БА. 1 base . 2 base в. 3 base4. What is a place of gold in a range of metal active reactions comparing to
hydrogen?А. Before б. Behind5. Who is author of the “Golden fish”tale? А. Б.Ринчен Б. Л. Н. Толстой В. А.С. Пушкин6. What kind phrase is “Brass can shine near the gold”? А. idiom б. folksay в. riddle
Conclusions