1. Which is the most reactive metal?
i. copper
ii. Gold
iii. Silver
iv. Iron
Ans: iv. Iron
2. Which of the following statement is correct ?
i. Bauxite is an ore of aluminium
ii. Haematite is an ore of silver.
iii. Pyrite is an ore of iron.
iv. Alluvial soil is an ore of copper.
Ans: i. Bauxite is an ore of aluminium
3. Which of the following mineral is called an ore ?
i. Metal present in less amount in mineral.
ii. Metals can be extracted from it.
iii. Metals can be extracted profitably from it.
iv. Metal present in minerals is useless.
Ans: iii. Metals can be extracted profitably from it.
5. Which one of the following is the ore of iron ?
i. argentite
ii. Magnetite
iii. Bauxite
iv. Chalcopyrite
Ans: ii. Magnetite
6. What is the process of heating ores with carbon in the absence of air called ?
i. reduction
ii. Roasting
iii. Smelting
iv. carbon-reduction
Ans: i. reduction
7. Distinguish between:
a. Roasting and calcinations
| Roasting | Calcinations |
| Roasting involves heating the ore in the presence of air, causing chemical changes, especially in sulfide ores, to convert them into oxides or other compounds. | Calcination is a process where the ore is heated in the absence or limited supply of air to drive off volatile substances like water, carbon dioxide, etc., leaving behind the desired oxide or carbonate. |
| Roasting requires the presence of air or oxygen for the reactions to occur. | Calcination is done in the absence or limited supply of air to prevent undesired oxidation. |
| Roasting is done at relatively higher temperatures compared to calcination. | Calcination is usually done at lower to moderate temperatures. |
b. Minerals and Ores
| Minerals | Ores |
| Minerals are natural substances in the Earth’s crust with a specific composition and structure. | Ores are rocks or minerals containing valuable materials like metals that can be extracted profitably. |
| Minerals are naturally occurring and can be used directly without further processing. | Ores require refining or processing to extract valuable materials. |
| Minerals: Quartz, feldspar, mica, and talc. | Ores: Iron ore (hematite), bauxite (aluminum ore), and copper ore (chalcopyrite). |
c. Highly reactive metals and less reactive metals
| Highly reactive metals | Less reactive metals |
| Highly reactive metals react easily with other things. | Less reactive metals don’t react as quickly. |
Highly reactive metals are used in chemicals and batteries. | Less reactive metals are used in structures and tools. |
| Highly reactive metals: potassium, sodium, calcium. | Less reactive metals: copper, silver, gold. |
8. Define mineral.
Ans: A mineral is a natural substance found in the Earth that has a specific chemical composition and structure.
9. What is an ore?
Ans: An ore is a type of rock or material found in nature that contains valuable minerals, like metals.
10. Write the main ores of iron, aluminium, copper and silver.
Ans: The main ores are:
Iron: Hematite
Aluminium: Bauxite
Copper: Chalcopyrite
Silver: Argentite
11. What is calcination of ores?
Ans: Calcination of ores is a process where a rock or mineral that contains a valuable substance is heated in a controlled way. The heating is done in an oven or furnace, without exposing it to air or with limited air supply.
12. Enlist the steps involved in the metallurgical process.
Ans: The steps involved in the metallurgical process are:
1. Mining
2. Crushing and Grinding
3. Concentration of Ore
4. Roasting or Calcination
5. Smelting
6. Purification of Metal
7. Electrolytic Refining
8. Casting
9. Alloying
10. Manufacturing and Usage
13. What is metallurgy?
Ans: Metallurgy the process of using heat and other techniques to work with rocks and minerals (like ores) to get valuable materials, usually metals.
14. Which method do you suggest for extraction of less reactivity metals?
Ans: For extracting less reactive metals, a common and effective method is heating with carbon or carbon reduction.
15. What is mineral ore used for?
Ans: Mineral ore is used for making metals, power and energy, building and construction.
16. Define gangue and slag.
Ans: Gangue is the useless part of the ore, like extra rock and impurities that don’t have the valuable metal or mineral.
Slag is the waste material left after we extract the metal from the ore, a bit like impurities that we remove to get the pure metal.
17. Name the process involved in refining ores.
Ans: The process involved in refining ores is called metallurgical refining.
18. Which metal is extracted from magnetite and argentite?
Ans: The metal extracted from magnetite is iron, and the metal extracted from argentite is silver.
19. Name some important methods of concentrating ores.
Ans: Some important methods of concentrating ores are:
1. Froth Floatation
2. Magnetic Separation
3. Gravity Separation
4. Leaching
20. Name any two reducing agents except carbon, used during smelting.
Ans:Besides carbon, two other reducing agents used during smelting are:
1. Hydrogen
2. Coke (which is almost pure carbon)
21. Enlist any three pure metals used in domestic appliances/articles and any two metals which you do not usually use as pure metals in your home.
Ans: Pure Metals Used in Domestic Appliances/Article
1. Aluminum
2. Copper
3. Iron
Metals Not Usually Used as Pure Metals in Home:
1. Tungsten
2. Titanium
22. How is the method of extracting the metals high up in the reactivity series different from the method of extracting other metals?
Ans: Method for Extracting Metals High Up in the Reactivity Series:
For metals high up in the reactivity series (like sodium, potassium), they’re so reactive that they can’t be extracted using simple methods like heating with carbon. Instead, a more complex process called electrolysis is used. In electrolysis, electric currents help separate the metal from compounds.
Method for Extracting Other Metals:
For metals lower in the reactivity series (like iron, copper), they can be extracted using simpler methods. Usually, heating the ore with carbon, known as smelting, is enough to get the metal out. The carbon grabs onto the oxygen in the ore, leaving the metal.
23. Write the principles of forth flotation process and electromagnetic separation.
Ans:
Froth Flotation Process:
Principle: Using bubbles to make valuable minerals stick, forming a froth that can be collected.
Purpose: Separating valuable minerals from waste based on their surface properties.
Electromagnetic Separation:
Principle: Using magnets to attract and separate magnetic metals from non-magnetic substances.
Purpose: Isolating and extracting metals based on their magnetic properties.
24. Name the methods by which a concentrated ore is changed into metallic oxide.State three objectives of roasting and calcination of ores.
Ans:
Methods to Change a Concentrated Ore into Metallic Oxide:
Roasting:
Method: Heating the ore in the presence of air.
Objective: To convert sulfide ores into oxides or to drive off unwanted volatile substances.
Calcination:
Method: Heating the ore in a limited or absence of air.
Objective: To remove volatile substances like water or carbon dioxide, leaving behind the metal oxide.
Objectives of Roasting and Calcination:
1. Removal of Volatiles:
Both roasting and calcination aim to remove volatile substances (like water, carbon dioxide) from the ore, making it more suitable for further processing.
2. Conversion to Oxides:
Roasting helps convert sulfide ores into oxides, while calcination also results in the formation of oxides, making the extraction of metals easier.
3. Improved Reactivity:
By eliminating volatile components and changing the ore into oxides, the resulting material becomes more reactive and suitable for subsequent metallurgical processes.
25. State the nature of the materials used for making cathodes and anodes in the electrolytic cell for refining copper.
Ans:
Materials for Making Cathodes and Anodes in Copper Refining:
Cathodes: The cathodes are usually made of thin sheets of pure copper. This helps attract and collect the copper ions from the electrolyte during the refining process, allowing them to build up and form a pure copper deposit.
Anodes: The anodes are typically made of impure copper, which needs to be refined. As the electric current flows through the electrolyte, copper atoms from the impure anode dissolve into the electrolyte as copper ions, ready to be deposited onto the cathodes, thus refining the copper.
28. All minerals are not ores but all ores are minerals.
Ans: Every ore is a mineral, but not all minerals are ores because Ores are valuable minerals containing extractable materials, while minerals are naturally occurring substances, and not all may have economic value for extraction.
29. Electrolytic process is used for the extraction of high reactive metals.
Ans: Electrolytic process is used for highly reactive metals because they are so clingy and reactive that using electricity helps us ‘unstick’ them from other elements, making extraction easier.
30. Gold is found in the free state.
Ans: Gold is found in the free state because it’s a ‘chill’ metal! Gold doesn’t easily react with other elements or substances, so it’s often found in its natural, pure form in the ground.
31. Gold ornaments look new even after several years of use.
Ans: Gold ornaments look new for a long time because gold doesn’t easily react with air, water, or chemicals.
32. Iron and aluminium do not freely occur in nature.
Ans: Iron and aluminum aren’t found alone in nature because they like to bond with other elements, forming compounds instead of existing in their pure form.
