Metals And Nonmetals Flashcards
(51 cards)
What is the activity series in metallurgy?
A ranking of metals based on their reactivity
This series helps determine the extraction methods for different metals.
Which metals are found in their free state?
Gold, silver, platinum, copper
These metals are less reactive and can exist naturally without combining with other elements.
What does it mean for a metal to be found in a combined state?
It exists as ores, such as sulphides or oxides
Copper and silver can be found in both free and combined states.
Which metals are never found in nature as free elements?
Na, Ca, Mg, Al
These metals are highly reactive and readily combine with other elements.
What types of ores are metals in the middle of the activity series typically found as?
Oxides, sulphides, carbonates
Examples include metals like iron (Fe) and lead (Pb).
What are the three categories of metals based on reactivity?
Low reactivity, medium reactivity, high reactivity
Each category requires different extraction techniques.
What is the first step in extracting pure metal from ores?
Concentration of ore
This step involves removing impurities from the ore.
What is calcination in the context of metallurgy?
Heating the ore to remove volatile substances
This process often involves converting carbonates to oxides.
What is the role of electrolysis in metal extraction?
To extract metals from molten ores
This method is used for metals of high reactivity.
Fill in the blank: The process of removing impurities from ores is called _______.
Enrichment of ores
This is essential before the metal extraction process.
True or False: The ores mined from the earth are typically pure and do not contain any impurities.
False
Ores are usually contaminated with impurities such as soil and sand.
What is roasting in metallurgy?
Heating sulphide ores in the presence of oxygen
This is done to convert them into oxides before reduction.
What is the final step in the extraction process of metals?
Purification of metal
This ensures the metal obtained is of high purity.
What is the primary purpose of separation techniques in metallurgy?
To remove gangue from the ore based on physical or chemical properties
Gangue refers to the unwanted material in ore that needs to be separated to extract the desired metal.
How can metals low in the activity series be extracted?
By heating their oxides to reduce them to metals
Metals low in the activity series are very unreactive, making them easier to extract through simple heating.
What is cinnabar and how is it processed to obtain mercury?
Cinnabar (HgS) is an ore of mercury; it is heated to convert it to mercuric oxide (HgO), which is then reduced to mercury
The chemical reaction involved is: 2HgS + 3O2 → 2HgO + 2SO2.
What happens to copper found as Cu2S in nature during extraction?
It is obtained by heating in air
The process involves roasting, which converts the sulphide ore to oxide.
What is roasting in metallurgy?
The process of converting metal sulphides into metal oxides by heating strongly in excess air
Roasting is essential for extracting metals from sulphide ores.
What is calcination?
The process of converting metal carbonates into metal oxides by heating strongly in limited air
Calcination is used for ores like zinc carbonate.
What is the chemical reaction for the calcination of zinc carbonate?
ZnCO3(s) → ZnO(s) + CO2(g)
This reaction illustrates the conversion of a carbonate ore to an oxide.
How are metal oxides reduced to their corresponding metals?
By using suitable reducing agents such as carbon
For example, ZnO(s) + C(s) → Zn(s) + CO(g).
What role do highly reactive metals play in the reduction of metal oxides?
They can be used as reducing agents in displacement reactions
Metals like sodium, calcium, and aluminium are examples of such reducing agents.
True or False: The extraction of metals from their compounds involves oxidation processes.
False
Extracting metals from compounds is a reduction process.
What is the process of electrolytic refining of copper?
The process involves using a solution of acidified copper sulphate where the anode is impure copper and the cathode is a strip of pure copper. As electric current passes, impurities dissolve and pure copper is deposited on the cathode.
