Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Metallurgy is the scientific and technological process used for the extraction of metals from their ores and refining them for use.
Minerals are naturally occurring inorganic substances found in the Earth's crust, while Ores are minerals from which a metal can be extracted profitably and conveniently.
Gangue refers to the unwanted earthy impurities like sand, clay, and rocky materials present in the ore.
Roasting is the process of heating sulfide ores strongly in the presence of excess air to convert them into metal oxides. For example: .
Calcination is the process of heating carbonate ores strongly in limited or no air to convert them into metal oxides. For example: .
Reduction is the process of obtaining metal from its oxide using reducing agents like Carbon () for medium reactivity metals, or through electrolysis for highly reactive metals like , , and .
Thermit Reaction involves the use of highly reactive metals like Aluminum () as reducing agents to displace metals of lower reactivity from their oxides, releasing a large amount of heat. Example: .
Electrolytic Refining is the process of purifying impure metals. The impure metal is made the anode (), a thin strip of pure metal is the cathode (), and the electrolyte is a solution of the metal salt.
📐Formulae
(Roasting of Zinc Blende)
(Calcination of Calamine)
(Reduction using Carbon)
(Thermit Reaction)
(Extraction of Mercury stage 1)
(Extraction of Mercury stage 2)
(Reaction at Cathode during Electrolytic Refining)
💡Examples
Problem 1:
Explain the process of extracting Copper from its sulfide ore (). Provide the necessary chemical equations.
Solution:
- Roasting: The ore is heated in air, partially converting it to oxide: . 2. Self-Reduction: On further heating, the remaining sulfide reacts with the formed oxide: .
Explanation:
Copper is a metal of low reactivity. Its sulfide ore, Copper Glance (), can be reduced to metal by simply heating it in the presence of air, where the oxide formed acts as an oxidizing agent for the remaining sulfide.
Problem 2:
Describe the electrolytic refining of Copper metal. What happens at the anode and cathode?
Solution:
At Anode (Oxidation): . At Cathode (Reduction): .
Explanation:
In this process, the impure copper block dissolves into the acidic copper sulfate electrolyte at the anode. Simultaneously, an equivalent amount of pure copper from the electrolyte is deposited onto the cathode strip.
Problem 3:
Why is the Thermit reaction used to join railway tracks?
Solution:
.
Explanation:
The reaction between Iron(III) oxide and Aluminum is highly exothermic. The heat generated is so intense that the iron produced is in a molten state, which can be poured into the cracks of railway tracks to join them.