阴离子表面活性剂:水中解离后,生成亲水性阴离子。特点

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问题:

阴离子表面活性剂:水中解离后,生成亲水性阴离子。特点

考点:精细化学工程表面活性剂表面活性剂题库
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用NA表示阿伏加德罗常数,下列说法正确的是(  )

A.11.2LH2所含的电子数为NA

B.3.9g钾所含有的电子的数目为0.1NA

C.0.5mol•L-1硫酸钾溶液1L中含有K+和SO42-离子的总数为NA

D.44gCO2含有的分子数为NA

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下列根式:
3
a2b
a3
b
a
3
2000
1
x
x2+y2
中,是最简二次根式的是______.
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阅读理解。

     The methods of practicing economy (实行节俭) are very simple. 1______ That is the first rule. A part

should always be set apart for the future. The person who spends more than he earns, is a fool.

     The next rule is to pay necessary money. 2______ The person who spends more than he earns tends to

get cheated; and if he often does so, he will easily get dishonest.

     Another method of economy is, to keep a regular account of all that you earn. An orderly man will know

beforehand what he requires, and will be provided with the necessary means for getting it. Thus his budget

will be balanced. 3______

     It is difficult to fix the limits of economy. Bacon says that if a man would live well within his income, he

ought not to spend more than one half, and save the rest. This is perhaps too exact. He himself didn't follow

his own advice. That depends on circumstances.

     Wherever there is a large family, the more money that is put to one side and saved, the better. Economy

is necessary to the rich, as well as to the comparatively poor man. 4______ If he spends all that he earns, he

can help nobody. He cannot properly educate his children, nor put them in the way of starting fairly in the

business of life?

     Saved money, however little, will serve to dry up many a tear; will avoid many sorrows and heart burnings, which otherwise might damage us. 5______

A. tie will not spend money as he likes.

B. Spend less than you earn.

C. Without economy, a man cannot be generous.

D. And his expense will be kept within his income.

E. You can not expect anyone help you economically.

F. Never run into debt.

G. By doing this, a person walks with a lighter step-his heart beats more cheerily.

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在MSC服务区内完成交换,管理和控制功能的是().

A.移动交换中心(MSC.

B.基台控制器(BSC.

C.操作和维护中心(OMC.

D.移动台(MS)

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Klenow fragment(Klenow片断)

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