2e-Acids, alkalis and titrations

Question 1

Question: What are the main methods for extracting metals?
Electrolysis

Answer 1

Answer:

Electrolysis: Used for highly reactive metals (e.g., aluminum, sodium, potassium).

Question 2

Question: What are the main methods for extracting metals?
Reduction with Carbon:

Answer 2

Reduction with Carbon: Used for metals less reactive than carbon (e.g., iron, zinc).

Question 3

Question: What are the main methods for extracting metals?
Native State:

Answer 3

Native State: Metals like gold and silver are found in their elemental form.

Question 4

Question: Why is electrolysis used to extract certain metals?

Answer 4

Answer: Highly reactive metals form stable compounds that cannot be reduced by carbon, so electrolysis is used to break these compounds.

Question 5

Question: Describe the extraction of iron using a blast furnace.Answer:

Answer 5

Raw materials: Iron ore (hematite), coke, and limestone.

Process:

Coke burns in hot air, producing carbon dioxide.

Carbon dioxide reacts with coke to form carbon monoxide.

Carbon monoxide reduces iron ore to molten iron.

Equations:C + O₂ → CO₂CO₂ + C → 2COFe₂O₃ + 3CO → 2Fe + 3CO₂

Question 6

Question: Why is carbon used to extract some metals?

Answer 6

Answer: Carbon is more reactive than certain metals and can displace them from their oxides.

Question 7

Question: What are alloys, and why are they useful?Answer:

Answer 7

Alloys are mixtures of metals with other elements, which improve properties like strength, corrosion resistance, and hardness.

Question 8

Question: Give examples of common alloys and their uses.

Answer 8

Answer:

Brass (Copper + Zinc): Musical instruments, door handles.

Bronze (Copper + Tin): Statues, medals.

Stainless Steel (Iron + Chromium + Nickel): Cutlery, surgical instruments.

Question 9

Question: Why is aluminum used for aircraft bodies and drinks cans?

Answer 9

Answer: Lightweight, corrosion-resistant, and strong when alloyed.

Question 10

Question: Why is copper used in electrical wiring and plumbing?

Answer 10

Answer: Good conductor of electricity and heat, malleable, and corrosion-resistant.

Question 11

Practical: Investigating Metal Extraction by Reduction

Method:

Answer 11

Heat copper(II) oxide with carbon in a crucible.

Observe the reduction of copper(II) oxide to copper.

Question 12

Practical: Investigating Metal Extraction by Reduction

Results and conclusion

Answer 12

Results:

A reddish-brown solid (copper) forms as carbon removes oxygen.

Conclusion:

Carbon can extract metals that are less reactive than itself.