问题 问答题

生命的孕育和维系需要水.

(1)如图为一简易净水器示意图.

①装置中活性炭层的作用是______,膨松棉层的作用是______.

②此简易净水器______(填“可以”或“不可以”)将硬水变成软水.

(2)请回答实验室制取蒸馏水的如下问题:

①在烧瓶中加入沸石的作用是______.

②弃去开始馏出的部分液体,往收集到的蒸馏水中加入肥皂水,振荡后可观察到的现象是______.

(3)用点滴板和右图所示装置进行电解水实验时,肥皂水液面上有气泡产生,点燃它会听到______.上述实验过程中发生的化学反应有(用化学方程式表示)

______,______

答案

(1)①活性炭能吸附水中的色素和异味,故装置中活性炭层的作用是吸附作用,膨松棉层的作用是 过滤掉水中的固体小颗粒.

②过滤只能除去难溶的物质,而可溶的钙镁化合物不能除去,因此得到的不是软水;

(2)①在烧瓶中加入沸石的作用是 防止液体暴沸.

②在蒸馏时加一些沸石,其目的是防治液体突然沸腾而影响实验.

(3)电解水生成氢气和氧气,氢气和氧气混合点燃会发生爆炸,在肥皂泡中点燃是会发出爆鸣声.

故答案为:(1)①吸附,过滤.

②不可以.

(2)①防止液体暴沸.

②有丰富的泡沫.

(3)爆鸣声. 2H2O

 通电 
.
 
2H2↑+O2↑,2H2+O2
 点燃 
.
 
2H2O.

解答题
单项选择题

Everyday some 16m barrels of oil leave the Gulf through the Strait of Hormuz. That is enough to fill a soft-drink can for everyone on earth, or to power every motor vehicle on the planet for 25 miles (40kin). Gulf oil accounts for 40% of global trade in the sticky stuff. More important, it makes up two-thirds of known deposits. Whereas at present production rates the rest of the world’s oil reserves will last for a mere 25 years, the Gulf’s will last for 100. In other words, the region’s strategic importance is set to grow and grow.

Or at least so goes the conventional wisdom, which is usually rounded out with scary talk of unstable supplies, spendthrift regimes and a potential fundamentalist menace. Yet all those numbers come with caveats. A great deal of oil is consumed by the countries that produce it rather than traded, so in reality the Gulf accounts for less than a quarter of the world’s daily consumption. As for reserves, the figures are as changeable as a mirage in the desert. The most comprehensive research available, conducted by the US Geological Survey, refers to an "expected" total volume for global hydrocarbon deposits that is about double current known reserves. Using that figure, and throwing in natural gas along with oil, it appears that the Gulf contains a more moderate 30% or so of the planet’s future fossil-fuel supplies. Leaving out the two Gulf states that are not covered in this survey--Iran and Iraq--the remaining six between them hold something like 20% of world hydrocarbon reserves, not much more than Russia.

All the same, it is still a hefty chunk; enough, you might think, to keep the people living atop the wells in comfort for the foreseeable future. But you might be wrong. At present, the nations of the Gulf Cooperation Council have a combined national income roughly equal to Switzerland’s, but a population which, at around 30m, is more than four times as big. It is also the fastest-growing on earth, having increased at nine times the Swiss rate over the past quarter-century. Meanwhile the region’s share of world oil trade has fallen, as has the average price per barrel.

As a result, the income per person generated by GCC oil exports has been diminishing since the 1970s. True, surging demand from America and Asia has recently boosted the Gulf’s share of trade, but the medium-term outlook for oil pries remains weak. Combined with continued growth in oil consumption, this should create sustained upward pressure on prices. And high oil prices will speed the search for alternatives. Who knows, in 20 years’ time fuel cells and hydrogen power may have started to become commercial propositions.

It is generally believed that oil produced in the Gulf()

A. will leave the locals in impoverished conditions

B. is less than the assessment in a conducted research

C. will diminish the region’s strategic importance

D. is traded rather than consumed by its producers