Metals And Nonmetals Flashcards
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.
What type of metals can be refined electrolytically?
Many metals such as copper, zinc, tin, nickel, silver, and gold can be refined electrolytically.
What is the role of the anode in electrolytic refining?
The anode is made of impure metal which dissolves into the electrolyte, allowing pure metal to deposit on the cathode.
During the electrolytic refining of copper, what happens to the impurities?
The impurities form what is known as anode mud and are removed from the process.
Fill in the blank: The electrolyte used in electrolytic refining of copper is a solution of _______.
acidified copper sulphate.
What is the thermite process used for?
The thermite process is used to join railway tracks or repair cracked machine parts through highly exothermic displacement reactions.
What happens at the cathode during electrolysis?
Metals are deposited at the cathode, which is the negatively charged electrode.
True or False: The metals high up in the reactivity series can be extracted by heating with carbon.
False.
Which metals cannot be reduced from their oxides by carbon?
Sodium, magnesium, and calcium.
What is produced when manganese dioxide is heated with aluminium powder?
Manganese and aluminium oxide are produced along with heat.
What type of reactions are displacement reactions in the context of metal extraction?
Displacement reactions are highly exothermic.
What is the general reaction for the electrolytic reduction of aluminium oxide?
Aluminium is obtained by electrolytic reduction of aluminium oxide.
Fill in the blank: Chlorine is liberated at the _______ during electrolysis.
anode.
What is the significance of the reactivity series in metal extraction?
It helps determine which metals can be extracted from their compounds and the methods required.
What are three methods to prevent the rusting of iron?
Painting, oiling, greasing
What is galvanisation?
A method of protecting steel and iron from rusting by coating them with a thin layer of zinc
True or False: A galvanised article is protected against rusting even if the zinc coating is broken.
True
What is alloying?
A method of improving the properties of a metal by mixing it with another substance
What elements are typically added to iron to create stainless steel?
Nickel and chromium
Fill in the blank: An alloy is a _______ mixture of two or more metals, or a metal and a non-metal.
homogeneous
What is the significance of 22 carat gold in jewelry making?
It means that 22 parts of pure gold is alloyed with 2 parts of either copper or silver
What is an amalgam?
An alloy where one of the metals is mercury
How do the electrical conductivity and melting point of an alloy compare to those of pure metals?
They are less than that of pure metals
What are two examples of alloys and their components?
- Brass: Copper and zinc (Cu and Zn)
- Bronze: Copper and tin (Cu and Sn)
What is solder and its components?
An alloy of lead and tin (Pb and Sn)
What is the height and weight of the iron pillar near the Qutub Minar in Delhi?
8 m high and weighs 6 tonnes (6000 kg)
How old is the iron pillar at Delhi?
More than 1600 years old
What was developed by ancient Indian iron workers to prevent rusting?
A process that prevents iron from rusting
