chem

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"What are the main categories of elements?"

"Metals and nonmetals are the two main categories of elements based on their physical and chemical properties."

"What is the key difference in electrical conductivity?"

"Metals are good conductors of heat and electricity

"What is malleability?"

"Malleability is the ability of metals to be hammered into thin sheets. For example

"What is ductility?"

"Ductility is the ability of metals to be drawn into wires. For example

"What is luster?"

"Luster is the ability of metals to reflect light from their surface and can be polished to shine

"What is Bauxite and what metal is extracted from it?"

"Bauxite (Al₂O₃·2H₂O) is the ore of Aluminum. It contains aluminum oxide with water molecules."

"What are the main ores of Copper?"

"Copper ores include:
• Malachite (CuCO₃·Cu(OH)₂)
• Cuprite (Cu₂O)
• Copper sulfide (Cu₂S)"

"What is Hematite and which metal comes from it?"

"Hematite (Fe₂O₃·2H₂O) is an important ore of Iron containing iron oxide with water."

"What is Rock salt and its formula?"

"Rock salt is an ore of Sodium with the chemical formula NaCl (sodium chloride)."

"What is Dolomite?"

"Dolomite (CaCO₃·MgCO₃) is an ore containing both Calcium and Magnesium carbonates."

"What is Hydraulic washing in ore processing?"

"Hydraulic washing separates gangue and lighter particles from ore using water flow."

"What is Froth floatation process?"

"Froth floatation concentrates sulfide ores by creating foam that selectively carries ore particles to the surface."

"What is Magnetic separation?"

"Magnetic separation uses magnets to separate magnetic materials like iron ore from non-magnetic impurities."

"What happens during roasting of Bauxite?"

"Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O
NaAlO₂ + 2H₂O → Al(OH)₃ + NaOH
2Al(OH)₃ → Al₂O₃ + 3H₂O"

"What is calcination and give an example?"

"Calcination heats carbonate ore in absence of air.
Example: ZnCO₃ → ZnO + CO₂ (zinc carbonate to zinc oxide)"

"What is roasting and give an example?"

"Roasting heats sulfide ore in open air.
Example: 2PbS + 3O₂ → 2PbO + 2SO₂ (lead sulfide to lead oxide)"

"What is self-reduction in metal extraction?"

"Self-reduction uses no external reagents.
2HgS + 3O₂ → 2HgO + 2SO₂
2HgO → 2Hg + O₂"

"What is carbon reduction for moderately reactive metals?"

"Carbon reduces metal oxides.
Examples:
ZnO + C → Zn + CO
Fe₂O₃ + 3C → 2Fe + 3CO"

"What is electrolytic reduction?"

"Electrolytic reduction uses electrical current for highly reactive metals.
Al₂O₃ → Al³⁺ + 3O²⁻
Al³⁺ + 3e⁻ → Al (molten)"

"What is liquation in metal refining?"

"Liquation separates metals by their different melting points - used for lead

"What is the electrolytic method of refining?"

"Electrolytic refining uses pure metal strip as cathode and impure metal block as anode to get pure metal."

"What is distillation in metal refining?"

"Distillation separates low boiling volatile metals like mercury and zinc from impurities."

"What is oxidation in refining (Bessemer converter)?"

"Oxidation removes impurities by converting them to oxides. Used for copper refining - converts Cu to CuO first."

"What is Van-Arkel method?"

"Van-Arkel method is used for zone refining

"What metals are high in the reactivity series?"

"K

"Give an example of metal displacement reaction."

"2CuS + 3O₂ → 2CuO + 2SO₂
2CuO + Cu₂S → 6Cu + SO₂ (copper extraction)"

"What happens when zinc reacts with carbon?"

"ZnO + C → Zn + CO
ZnO + CO → Zn + CO₂ (zinc extraction from zinc oxide)"

"How is aluminum extracted by carbon reduction?"

"Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + Δ (aluminum acts as reducing agent due to high reactivity)"

"What causes corrosion of metals?"

"Corrosion occurs when metals react with oxygen and moisture.
4Fe + 3O₂ → 2Fe₂O₃
Fe₂O₃ + xH₂O → Fe₂O₃·xH₂O"

"How does copper corrode?"

"2Cu + CO₂ + O₂ + H₂O → CuCO₃·Cu(OH)₂ (forms green patina on copper surfaces)"

"What is rusting and its chemical equation?"

"Rusting of iron:
2Fe + 3H₂S → Fe₂S₃ + 3H₂ (iron reacts with hydrogen sulfide to form iron sulfide)"

"List 6 methods to prevent rusting."

"1. Oiling/greasing
2. Painting/galvanizing
3. Galvanization
4. Electroplating with Sn

"What are the three types of alloys and give examples?"

"1. Ferrous - Ni steel

"What are the main objectives of making alloys?"

"1. Hardness
2. Hardness
3. Tensile strength
4. Melting point
5. Chemical reactivity
6. Electrical conductivity"

"Name 5 examples of metals"

"Copper

"Name 5 examples of nonmetals"

"Phosphorus

"Which nonmetal is liquid at room temperature?"

"Bromine is the only nonmetal that is liquid at room temperature."

"Which is the best conductor of electricity?"

"Silver is the best conductor of electricity among all metals."

"What are the seven diatomic nonmetals?"

"H₂

"Which metals are soft enough to cut with a knife?"

"Sodium and potassium are soft metals that can be cut with a knife."