问题 填空题

工业上合成氨的主要生产过程有:

(1)原料气的制备、净气和压缩。氮气来源于________,氢气来源于________,净化原料气的原因是__________________________________________________________。

(2)氨的合成。在________中进行,反应的最佳条件是_______________________________________________________________。

(3)氨的分离。如将N2、H2按体积比1∶3进入合成塔,从合成塔出来的混合气中通常含体积分数为15%左右的氨气,则出来的混合气体中含H2的体积分数为________,N2的体积分数为________。

答案

(1)空气 水和碳氢化合物 防止催化剂中毒

(2)合成塔 压强20~50 MPa,温度400~500 ℃,铁触媒作催化剂

(3)63.75% 21.25%

(3)设起始N2、H2的体积分别为1、3,反应中转化的N2的体积为x,则

N2(g)+3H2(g)2NH3(g)

起始体积 1   3        0

平衡体积 1-x  3-3x       2x

依题意:

×100%=15%

解得:x=

故φ(H2)=×100%=63.75%

φ(N2)=1-φ(H2)-φ(NH3)=21.25%

阅读理解

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CHICAGO (Reuters) - Smoking not only can wrinkle(起皱纹) the face and turn it yellow -- it can do the same to the whole body, researchers reported on Monday.

The study, published in the Archives of Dermatology, shows that smoking affects the skin all over the body -- even skin protected from the sun.

"We examined non-facial skin that was protected from the sun, and found that the total number of packs of cigarettes smoked per day and the total years a person has smoked were linked with the amount of skin damage a person experienced," Dr. Yolanda Helfrich of the University of Michigan, who led the study, said in a statement.

"In participants older than 65 years, smokers had significantly more fine wrinkling than nonsmokers. Similar findings were seen in participants aged 45 to 65 years," Helfrich's team added in their report.

The researchers tested 82 people, smokers and nonsmokers, taking pictures of the inner right arms. They ranged in age from 22 to 91 and half were smokers Independent judges decided how wrinkled each person's skin was.

When skin is exposed to sunlight, notably the face, it becomes coarse, wrinkled and discolored with a pale yellow tint, Helfrich's team wrote.

Several previous studies have found that cigarette smoking contributes to premature(过早的)skin aging as measured by facial wrinkles, the study said, but little has been done to measure the aging of skin not exposed to light.

The report did not discuss the mechanism involved but previous research has found that cigarette smoke, among other things, causes blood vessels(血管)beneath the skin to constrict(紧缩), reducing blood supply to the skin.

Smoking can also damage the connective tissue that supports both the skin and the internal organs.

66. The best title for this passage would be_______.

A. The danger of smoking        B. A survey of smokers

C. Quit smoking for health       D. Smoking causes skin aging

67.  how wrinkled each person's skin doesn’t relate to_______.

A. the number of cigarettes a person smokes

B. the kind and characteristics of skin

C. how long a person smokes

D. how long skin is under sunlight

68. It can be inferred from the study _______.

A. smoking won’t make skin protected from the sun age

B. smoking will do damage to skin rather than other organs

C. smokers over 65 usually won’t worry about their skin

D. the age of smokers is not connected with the result of the test

69. From the passage smoking results in skin aging mainly because_____.

A. it will lower blood supply to skin.

B. it can make you feel tired

C. it can make skin come off

D. it can make blood run faster

70. The main purpose of the passage is to ______.

A. inform people about the result of the study

B. advise people to how to protect skin

C. warn people not to smoke again.

D. introduce a new way of avoid skin aging

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