(i) Mineral: The naturally ocurring compounds of element are known as Mineal.
(ii) Or: Minerals from which metals can be extractred profitably are known as ores.
(iii) Gangue: The impurities present in the ore such as sand, rocks etc are nonas gangue.2. Two metals commonly found in nature in their free state are gold (Au) and silver (Ag). These metals are relatively unreactive, which allows them to exist in their pure, metallic form without combining with other elements. 3. The chemical process used to obtain a metal from its oxide is called reduction. This involves using a reducing agent to remove the oxygen from the metal oxide, resulting in the free metal. Reducing agents like carbon, hydrogen, or more reactive metals like aluminum can be used.
Elaboration:
Reduction:
Reduction is the process of removing oxygen from a metal oxide.
Reducing Agents:
Various substances can act as reducing agents, such as carbon, hydrogen, or other metals like aluminum.
Example:
For instance, iron oxide (Fe₂O₃) can be reduced to iron (Fe) by reacting it with carbon (C) in a blast furnace. The reaction is: 2Fe₂O₃ + 3C → 4Fe + 3CO₂.
Electrolysis:
For metals that are higher in the reactivity series, electrolysis can be used to obtain the metal from its oxide.
Calcination and Roasting:
These processes are used to convert sulfide or carbonate ores into oxides, making them easier to reduce. Calcination is heating in the absence of air, while roasting is heating in the presence of air.