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Question (41)

QN0035962

Sulphide ores are converted into oxides by heating in excess air. What is this process called?

(A) Calcination
(B) Roasting
(C) Electrolysis
(D) Refining

Correct Answer: B

Explanation:

Roasting is the process of heating sulphide ores strongly in excess air to convert them into oxides.

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Question (42)

QN0035963

Carbonate ores are converted into oxides by heating in limited or no air. What is this process called?

(A) Roasting
(B) Calcination
(C) Electroplating
(D) Alloying

Correct Answer: B

Explanation:

Calcination involves heating carbonate ores in limited or no air to convert them into oxides.

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Question (43)

QN0035964

Why are metal oxides reduced during extraction of moderately reactive metals?

(A) To remove oxygen from the metal oxide
(B) To add oxygen to the metal
(C) To form an acid
(D) To increase the gangue content

Correct Answer: A

Explanation:

Reduction removes oxygen from the metal oxide and produces the metal.

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Question (44)

QN0035965

A metal oxide is heated with carbon and produces the metal. What role does carbon play?

(A) Oxidising agent
(B) Reducing agent
(C) Catalyst only
(D) Flux only

Correct Answer: B

Explanation:

Carbon removes oxygen from the metal oxide, so it acts as a reducing agent.

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Question (45)

QN0035966

In the thermit reaction, aluminium is used to reduce certain metal oxides. Why can aluminium perform this reaction?

(A) Aluminium is less reactive than the metal
(B) Aluminium has a strong affinity for oxygen
(C) Aluminium is a non-metal
(D) Aluminium does not react with oxygen

Correct Answer: B

Explanation:

Aluminium has a strong affinity for oxygen and can reduce oxides of certain metals such as iron.

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Question (46)

QN0035967

A metal is highly reactive and cannot be extracted by reduction with carbon. Which method is suitable?

(A) Electrolysis
(B) Simple filtration
(C) Decantation
(D) Crystallisation only

Correct Answer: A

Explanation:

Highly reactive metals are generally extracted by electrolytic reduction of their molten compounds.

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Question (47)

QN0035968

During electrolytic refining of a metal, where is the pure metal deposited?

(A) At the anode
(B) At the cathode
(C) In the electrolyte surface
(D) Outside the electrolytic cell

Correct Answer: B

Explanation:

During electrolytic refining, pure metal is deposited at the cathode.

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Question (48)

QN0035969

Iron articles are exposed to moist air and gradually develop a reddish-brown coating. What process is occurring?

(A) Alloying
(B) Rusting
(C) Roasting
(D) Calcination

Correct Answer: B

Explanation:

Iron reacts with oxygen and moisture to form rust, a reddish-brown coating.

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Question (49)

QN0035970

Why does galvanisation help protect iron from corrosion?

(A) Zinc prevents contact of iron with air and moisture and also provides protection if the coating is damaged
(B) Zinc converts iron into a non-metal
(C) Zinc removes all oxygen from the atmosphere
(D) Zinc increases the melting point of iron

Correct Answer: A

Explanation:

A zinc coating protects iron from contact with air and moisture, and zinc can also provide sacrificial protection when the coating is damaged.

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Question (50)

QN0035971

Why are alloys often preferred over pure metals for particular applications?

(A) They always have lower strength
(B) Their properties can be modified to suit specific uses
(C) They are always non-conductors
(D) They cannot be heated

Correct Answer: B

Explanation:

Alloys are mixtures of metals or metals with other elements and are made to obtain useful properties for specific applications.

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Question (41)

Sulphide ores are converted into oxides by heating in excess air. What is this process called?

Explanation:

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Question (42)

Carbonate ores are converted into oxides by heating in limited or no air. What is this process called?

Explanation:

Link:

Question (43)

Why are metal oxides reduced during extraction of moderately reactive metals?

Explanation:

Link:

Question (44)

A metal oxide is heated with carbon and produces the metal. What role does carbon play?

Explanation:

Link:

Question (45)

In the thermit reaction, aluminium is used to reduce certain metal oxides. Why can aluminium perform this reaction?

Explanation:

Link:

Question (46)

A metal is highly reactive and cannot be extracted by reduction with carbon. Which method is suitable?

Explanation:

Link:

Question (47)

During electrolytic refining of a metal, where is the pure metal deposited?

Explanation:

Link:

Question (48)

Iron articles are exposed to moist air and gradually develop a reddish-brown coating. What process is occurring?

Explanation:

Link:

Question (49)

Why does galvanisation help protect iron from corrosion?

Explanation:

Link:

Question (50)

Why are alloys often preferred over pure metals for particular applications?

Explanation:

Link:

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