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问题 填空题

（6分）海洋中蕴含丰富的资源。

（1）海水淡化是解决淡水不足的重要方法。下列净水方法中，可以使海水变为淡水的是         （填字母序号）。

A．过滤       B．吸附     C． 沉降       D． 蒸馏

（2）从海水中提炼出来的重水(D2O)可作原子能反应堆的中子减速剂和传热介质，重水中的重氢原子（D）核内有一个质子、一个中子。则重水中氧元素的质量分数为         。

（3）下图是采用膜分离技术的海水淡化装置，加压后，只有水分子可以通过淡化膜，其他 粒子不能通过淡化膜。加压前后，装置右侧海水中，下列各量减小的是       。

①溶质质量分数 ②溶剂质量  ③溶液质量   ④溶质质量

（4）从海水中制备食盐和金属镁的流程如下所示：

回答下列问题：

①步骤Ⅱ中需加入一种试剂并进行浓缩，所加试剂是         。

②粗盐中含有泥沙等杂质，用粗盐制取精盐的实验方法是         。

③上述流程中的反应不包含的基本反应类型是         。

答案

（1）D    （2）80%      （3）②③

（4）①稀盐酸     ②溶解——过滤——蒸发     ③置换反应

题目分析：（1）A、过滤是除去不溶性杂质的方法，不能除去水中的可溶性物质，故错误；B、吸附是除去水中色素、异味等不溶性杂质的一种方法，不能除去水中的氯化钠、氯化镁等可溶性盐，故错误；C、沉降是使大颗粒不容物快速沉淀下来，不能除去水中的可溶性物质，故错误；D、蒸馏是通过加热的方法将水变成水蒸气，再冷凝成水的方法，可以得到最纯的蒸馏水，故可将水淡化，正确；（2）重水中的重氢原子的相对原子质量为2，则氧元素质量分数为：×100%=80%；（3）海水中溶剂是水，由水分子可以透过淡化膜进入左侧淡水池，而海水中的各种离子不能透过淡化膜，说明加压后右侧海水中溶剂减少，溶质不变，所以溶液质量也减少，由于溶质不变，所以溶质质量分数增大，故②③正确；（4）①氢氧化镁为白色沉淀，与盐酸反应生成氯化镁；②粗盐中含有泥沙等杂质，用粗盐制取精盐的实验方法是溶解、过滤、蒸发；③把贝壳制成石灰乳，涉及反应：CaCO3 高温CaO+CO2↑、CaO+H2O═Ca（OH）2，分别属于分解反应、化合反应；在引入的海水中加入石灰乳，沉降、过滤、洗涤沉淀物，涉及反应：MgCl2+Ca（OH）2═Mg（OH）2↓+CaCl2，属于复分解反应；将沉淀物与盐酸反应，结晶、过滤、干燥产物，涉及反应：Mg（OH）2+2HCl=MgCl2+2H2O，MgCl2•6H2O△MgCl2+6H2O，分别属于复分解反应、分解反应；将产物电解得到金属镁，涉及反应：MgCl2通电Mg+Cl2↑，属于分解反应；没有涉及的反应为置换反应．

问答题

(46)The climatic phenomenon that is being blamed for floods, hurricanes and early snowstorms also deserves credit for encouraging plant growth and helping to control the pollutant linked to global warming, a new study shows.
E1 Nino—the periodic warming of eastern Pacific Ocean waters—causes a burst of plant growth throughout the world, and this removes carbon dioxide from the atmosphere, researchers have found.
(47)The new study shows that natural weather events，such as the brief warming caused by E1 Nino, have a much more dramatic effect than previously believed on how much carbon dioxide is absorbed by plants and how much of the gas is expelled by the soil.
Atmospheric carbon dioxide, or CO2, has been increasing steadily for decades. This is thought to be caused by an expanded use of fossil fuels and by toppling of tropical forests. Scientists have linked the CO2 rise to global warming, a phenomenon known as the greenhouse effect. (48)Alarmed, nations of the world now are drawing up new conservation policies to reduce fossil fuel burning, in hopes of reducing greenhouse gases in the atmosphere.
But David Schimel of the National Center for Atmospheric Research，a co-author of the new study, says that before determining how much to reduce fossil fuel burning we should consider the effects of natural climate variations on the ability of plants to absorb CO2.
Schimel said satellite measurements of CO2, plant growth and temperature show that natural warming events such as E1 Nino at first cause more CO2 to be released into the atmosphere, probably as the result of accelerated decay of dead plant matter in the soil. But later, within two years, there is an explosion of growth in forests and grasslands, which means plants suck more carbon dioxide out of the atmosphere.
" We think that there is a delayed response in vegetation and soil to the warming effects of such phenomena as E1 Nino, and this leads to increased plant growth, " said Schimel.
(49)However, he said, it is not clear whether the warming by E1 Nino causes a net decrease in the buildup of CO2 over the long haul. " We don’t really know that yet, " said Schimel. What the study does show, however, is that the rise and fall of CO2 in the atmosphere is ply influenced by natural changes in global temperature, said B. H. Braswell of the University of New Hampshire, another co-author of the study.
Braswell said that in years when the global weather is cooler than normal, there is a decrease in both the decay of dead plants and in new plant growth. This causes an effect that is the opposite of E1 Nino warming: CO2 atmosphere levels first decline and later increase.
(50) " I think we have demonstrated that the ecosystem has a lot more to do with climate change than was previously believed," said Braswell, " Focusing on the role of human activity in climate change is important, but manmade factors are not the only factors. \
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单项选择题

某初孕妇，28岁，34周妊娠，睡眠中突然出现 * * 大量流液，此后起床活动时有持续流液，因胎膜早破收入院。

胎膜早破的确诊方法有

A． * * 检查

B．肛门检查

C． * * 液pH值不变

D．取 * * 后穹窿黏液涂片观察到羊齿状结晶

E．B超观察羊水池深度
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