Chemistry MC

[匿名]

2010-10-25 3:58 am

Question 16:
A odourant is added to Hong Kong Town Gas so as to
A. increase the density of Town Gas.
B. warn consumers against leakage of Town Gas.
C. ensure Town Gas give the correct amount of energy on combustion.
D. make Town Gas undergo complete combustion.
Question 17:
Leakage of town gas is dangerous because
(1) carbon monoxide in town gas is highly poisonous and causes death on
inhalation.
(2) town gas can explode if ignited.
(3) town gas has a bad smell.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. All of them
Question 18:
When crude oil is fractionally distilled, the first fractions obtained, compared to
later fractions,
(1) have lower boiling points.
(2) are more volatile.
(3) are more viscous.
A. (1) only
B. (2) only
C. (1) and (2) only
D. (1) and (3) only
E. (2) and (3) only

Question 21:
Which of the following hydrocarbons would most probably be present in petrol?
A. C2H6
B. C4H8
C. C4H10
D. C6H14
Question 22:
Liquefied petroleum gas (LPG) consists mainly of
A. butane
B. carbon monoxide
C. hydrogen
D. methane

回答 (1)

andrew

2010-10-25 7:06 am

✔ 最佳答案

Question 16:
The answer is: B. warn consumers against leakage of Town Gas.

People will alert the leakage of town gas when they smell the odourant.

----------
Question 17:
The answer is: A. (1) and (2) only

(1) is true. Carbon dioxide is highly poisonous.

(2) is true. Explosion occurs when the mixture of town gas and air is ignited.

(3) is false. An odourant is added to town gas in order to warn people in case of leakage of town gas. Actually, this is not hazardous.

----------
Question 18:
This answer is: C. (1) and (2) only

When compared with later fractions, the first fractions have lower boiling points, are more volatile, and are less viscous.

----------
Question 21:
The answer is: D. C6H14

At room temperature, D is a liquid, while A, B and C are gases.

----------
Question 22:
The answer is: A. butane

All of A, B, C and D are gases at room temperature. A is most likely to be liquefied by increasing pressure as its boiling point (-0.5°C) is close to room temperature.

參考: andrew

👍 0 👎 0