在20mL0.l0mol•L-1HCl溶液中逐滴加入0.20mol•L-1氨水,

题型:选择题

问题:

在20mL 0.l0mol•L-1 HCl溶液中逐滴加入0.20mol•L-1氨水,容液pH和加入的氨水的体积关系曲线如右图所示,有关微粒浓度大小关系正确的是(  )

A.A、B间的溶液中可能有:c(Cl-)>c(NH4+)>c(H+)>c(OH-

B.B点:c(Cl-)=c(NH4+)>c(OH-)=c(H+),且a=10.0

C.C点:c(NH4+)>c(Cl-)>c(H+)>c(OH-

D.D点:c(Cl-)>c(NH4+)>c(OH-)>c(H+

考点:粒子浓度大小的比较沉淀溶解平衡溶液pH的有关计算
题型:选择题

星期天,亮亮从家里骑车出发向东走了2千米到达小明家,继续走了0.5千米到达小美家,然后向西走了5.5千米到达王老师家,最后回到自已家。

(1)以亮亮家为原点,以向东的方向为正方向,用1个单位长度表示1千米,请你在数轴上表示出小明家,小美家,王老师家的位置;

(2)王老师家距小明家多远?

(3)亮亮一共骑了多少千米的路程?(列式计算)

题型:选择题

预存式自体输血的标准是()。

A.血红蛋白大于105g/L,红细胞比容不低于31%

B.血红蛋白大于115g/L,红细胞比容不低于36%

C.血红蛋白大于100g/L,红细胞比容不低于30%

D.血红蛋白大于110g/L,红细胞比容大于33%

E.血红蛋白大于108g/L,红细胞比容不低于32%

题型:选择题

Most people would be (1) by the high quality of medicine (2) to most Americans. There is a lot of specialization, a great deal of (3) to the individual, a (4) amount of advanced technical equipment, and (5) effort not to make mistakes because of the financial risk which doctors and hospitals must (6) in the courts if they (7) things badly.

But the Americans are in a mess. The problem is the way in (8) health care is organized and (9) . (10) to pubic belief it is not just a free competition system. The private system has been joined a large public system, because private care was simply not (11) the less fortunate and the elderly.

But even with this huge public part of the system, (12) this year will eat up 84.5 billion dollars—more than 10 percent of the U. S. Budget—large number of Americans are left (13) . These include about half the 11 million unemployed and those who fail to meet the strict limits (14) income fixed by a government trying to make savings where it can.

The basic problem, however, is that there is no central control (15) the health system. There is no (16) to what doctors and hospitals charge for their services, other than what the public is able to pay. The number of doctors has shot up and prices have climbed. When faced with toothache, a sick child, or a heart attack, all the unfortunate persons concerned can do is (17) up. Two thirds of the population (18) covered by medical insurance. Doctors charge as much as they want (19) that the insurance company will pay the bill.

The rising cost of medicine in the U. S. A. is among the most worrying problems facing the country. In 1981 the country’s health bill climbed 15.9 percent--about twice as fast as prices (20) general.

20()

A.in

B.with

C.on

D.for

题型:选择题

液压缸工作时速度下降的原因是()。

A.活塞杆刚性差

B.安装位置不正确

C.缸筒拉伤

D.活塞与活塞杆的同轴度不当

题型:选择题

已洗混合份的比色应小于().

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