1999 年

化學 · 共 50 題 · 點擊選項即時核對答案

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41.

Plastic X has the following structure :

Which of the following statements concerning X are correct ?

(1)The monomer of X is CHCl=CHCl.

(2)X can be used to make electric sockets.

(3)The flue gas produced by the incineration of X can cause the formation of acid rain.

42.

Consider the following experiment :

Which of the following statements concerning the experiment are correct ?

(1)Gas bubbles are evolved at electrode X.

(2)An orange colour gradually appears in the solution around electrode Y.

(3)The experiment can be used to show that ions migrate towards oppositely charged electrodes.

43.

Which of the following statements concerning a soapless detergent are correct ?

(1)It can be prepared by heating a cooking oil with sodium hydroxide solution.

(2)It acts as a wetting agent by reducing the surface tension of water.

(3)It acts as an emulsifying agent in the cleaning process.

44.

Which of the following statements concerning the reaction of an alkane with bromine are correct ?

(1)The reaction occurs faster under sunlight than in darkness.

(2)The reaction is a substitution reaction.

(3)The colour of the reaction mixture fades.

45.

For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Sulphur is classified as a non-metal.	Sulphur does not react with dilute acids.

46.

For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Metals have good thermal conductivity.	Metals are composed of giant lattices of positive ions surrounded by valence electrons which are free to move throughout the lattices.

47.

For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Adding potassium nitrate to soil can increase crop yield.	Potassium nitrate can provide the essential elements for plant growth.

48.

For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Local tap water produces a scum with soap.	Water containing calcium ions can form an insoluble compound with soap.

49.

For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Water-type fire extinguisher is suitable for putting out a fire caused by kerosene.	Water can cut off the supply of oxygen for a fire caused by kerosene.

50.

For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Codeine, which is an ingredient of some cough mixtures, may cause drowsiness.	Codeine is addictive.