Chemistry
Heating an ore in a limited supply of air or in the absence of air at a temperature just below it's melting point is known as :
- Smelting
- Ore dressing
- Calcination
- Bessemerisation
Related Questions
Aluminium powder is used in thermite welding because :
- it is strong reducing agent
- it is strong oxidizing agent
- it is corrosion resistant
- it is a good conductor of heat.
Using the information below about X and Y – complete the following questions :
X-2,8,7 Y-2,8,2 Dissolves in water and turns blue litmus red Very low solubility in water. Dissolves in HCl Tends to oxidise elements and compounds Tends to act as a reducing agent Poor electrical and thermal conductivity Good electrical and thermal conductivity No tendency to form alloys Forms alloys (i) …………… is the metallic element.
(ii) Metal atoms tend to have a maximum of …………… electrons in the outermost energy level.
(iii) Non-metallic elements tend to form …………… oxides while metals tend to form …………… oxides.
(iv) Non-metallic elements tend to be …………… conductors of heat and electricity.
(v) Metals tend to …………… electrons and act as …………… agents in their reactions with elements and compounds.
The following questions relate to the extraction of aluminium by electrolysis :
(i) Name the other aluminium containing compound added to alumina and state it's significance.
(ii) Give the equation for the reaction that takes place at the cathode.
(iii) Explain why is it necessary to renew the anode periodically.
State the main components of the following alloys :
(i) Brass
(ii) Duralumin
(iii) Bronze.