Extraction of metals：練習問題

What is the name of the main ore of aluminium from which the metal is industrially extracted?

Which statement correctly describes the relationship between a metal's position in the reactivity series and its method of extraction?

During the extraction of aluminium by electrolysis, which ionic half-equation occurs at the negative electrode (cathode)?

In the extraction of iron in the blast furnace, limestone (\( \text{CaCO}_3 \)) is added. What is the primary purpose of adding limestone?

What is the specific function of cryolite in the electrolytic extraction of aluminium?

Describe the role of limestone (\(\text{CaCO}_3\)) in the extraction of iron from its ore in the blast furnace and identify the byproduct formed by this reaction.

In the extraction of aluminium by electrolysis, explain why the carbon anodes must be replaced periodically and provide the balanced chemical equation for the reaction causing this loss.

The extraction method for a metal depends on its reactivity.

(a) Copper is a moderately reactive metal that can be extracted from its ore, copper(II) carbonate ( \(\text{CuCO}_3\) ). Describe the chemical principle and main reactions involved in extracting copper from copper(II) carbonate. Write a balanced chemical equation for the reduction step.

(b) In contrast, aluminium is a very reactive metal. Explain why aluminium cannot be extracted by the same method as copper. Briefly describe the industrial method used for aluminium extraction and state the reason why this method is preferred for reactive metals.

(c) Metal extraction processes can have significant environmental impacts. Discuss two distinct environmental problems that can arise from large-scale metal extraction and suggest one method to reduce the impact of one of these problems.

Zinc is extracted from its main ore, zinc blende (\(\text{ZnS}\)).
(a) Describe the first stage of extraction where the ore is heated strongly in a supply of air.
(b) The product of the first stage is then reduced in a furnace. Identify the reducing agent and write a balanced symbol equation for this reduction.
(c) Explain why the zinc is produced as a vapor in the furnace and describe how it is collected.