化學其他 DSE、CE 選擇題（第 8 頁）

71.

Iron pyrite (FeS₂) looks like gold and its common name is "fool's gold". Which of the following methods can be used to distinguish iron pyrite from gold ?

(1)comparing their densities

(2)comparing their electrical conductivity

(3)comparing the effect of heat on them

72.

For each of the following questions, 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 statements are true and the 2nd statement is a correct explanation of the 1st statement.

B.Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.

C.The 1st statement is false but the 2nd statement is true.

D.Both statements are false.

1st statement	2nd statement
Polyethene is used for making the handle of frying pans.	The shape of the polyethene handle remains unchanged during the frying process.

73.

For each of the following questions, 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 statements are true and the 2nd statement is a correct explanation of the 1st statement.

B.Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.

C.The 1st statement is false but the 2nd statement is true.

D.Both statements are false.

1st statement	2nd statement
Sodium carbonate can be used to soften hard water which contains calcium ions.	Sodium carbonate reacts with calcium ions in hard water to form a precipitate.

74.

Which of the following compounds, when dissolved in water, gives a green solution?

75.

Sodium chromate, Na₂CrO₄, dissolves in water to give a yellow solution. When dilute hydrochloric acid is added to the solution, the following reaction occurs: 2CrO₄²⁻(aq) + 2H⁺(aq) → Cr₂O₇²⁻(aq) + H₂O(l) Which of the following statements concerning this reaction is correct ?

76.

Which of the following reactions does NOT require the use of a catalyst?

77.

Which of the following set-ups can be used to dry moist sulphur dioxide gas?

78.

In which of the following is ammonia used?

(1)the manufacture of nitric acid

(2)the making of fertilizers

(3)the making of antiacids

79.

In which of the following processes will carbon dioxide be produced?

(1)the fermentation of glucose solution

(2)the biodegradation of animal faeces

(3)the treatment of car exhaust in a catalytic converter

80.

For each of the following questions, 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 statements are true and the 2nd statement is a correct explanation of the 1st statement.

B.Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.

C.The 1st statement is false but the 2nd statement is true.

D.Both statements are false.

1st statement	2nd statement
Combustion of diamond gives carbon dioxide.	Diamond is a crystalline form of carbon.