Chemistry online class

Grade 7 and 9 exam results are out.

Every exam paper has "HOT" and "LOT" question... HOT is high order thinking questions and LOT is low order thinking question. Questions based on memorisation are LOT while those based on application are HOT.. Good evening chemists.

Gold.

Gold is a chemical element; it has chemical symbol Au (from Latin aurum) and atomic number 79. In its pure form, it is a bright-metallic-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals.

Ore of gold.
There are about 8 ores from which gold can be extracted from.
1.Quartz gold ore
2. Silver-gold ore
3. Iron oxide copper gold ore
4. Gold sulfide ore
5. Blue clay gold ore
6. Tellurium gold ore
7. Gold in arsenopyrite
8. Granite gold ore.

Extraction of gold.
Gold is extracted from ore through physical processes like crushing and gravity separation (panning) or chemical processes like cyanide leaching, which dissolves the gold from the ore. The most common modern method is cyanide leaching and other advanced methods however physical and gravitation separation is common practice at our gold mines here in zambia.

1. Physical and gravity separation
- Crushing and grinding: Large rocks containing gold are first crushed and then ground into a fine powder. Using running water, the powder is passed over a series of rifles , which trap the gold particles while allowing the other minerals to pass through.

-Panning: A simple method using a pan and water to separate heavier gold particles from lighter sand and gravel, often used by individual prospectors.

-Mercury amalgamation: this is when mercury is added to a pan cantaining heavier gold particles, lighter sand and gravel. Mercury combines with gold and forms an amalgam. The amalgam is then heated to boil off the mercury, leaving the pure gold behind.

2. Cyanide leaching
This method is used for gold ores that are amenable to cyanide leaching, such as free-milling and some refractory ores. The ore is crushed and then mixed with a cyanide solution, which dissolves the gold. The gold is then recovered from the solution by adsorption onto activated carbon or by precipitation with zinc dust.

Uses of gold
1.Jewelry: The Primary Use of Gold
2. electronics: Gold parts are used in cell phones, computers and many other electronics.
3. in medicine: gold is used in Dentistry, surgical instruments.
4. in aerospace: Gold is used in satellite components.
5. in Awards and Status Symbols.
Etc

Gold recycling: Gold is used and reused, and reused again.

Because gold is so valuable, there are so many buyers, and because gold is so easy to recycle, it has become one of the world's most recycled metals.

I will share pictures of my recent visit at the one of the gold mines. Stay glued.

Good morning chemist's

Extraction of gold should be introduced in our secondary school chemistry syllabus.
I will share notes on how gold is processed on a small scale. Good afternoon chemists.

All alkalis are Bases but not all bases are alkalis. Good afternoon chemists.

Wishing you boys all the best in your exams.

Which law states that the amount of chemical change being produced by a current at an electrode-electrolyte interface is proportional to the quantity of electricity? Good evening chemists

Good morning chemist's . Have a great day.