小明用右图所示装置探究可燃物燃烧的条件.他发现热水中的白磷熔化成白色小液滴,不久

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问题:

小明用右图所示装置探究可燃物燃烧的条件.他发现热水中的白磷熔化成白色小液滴,不久,铜片上的白磷开始燃烧,而红磷及水中的白磷都不燃烧.请回答:

(1)可燃物燃烧需要同时满足的条件是______.

(2)实验完毕,小明将烧杯中的热水慢慢倒出,水快倒完时,小明发现白磷刚露出水面就剧烈燃烧起来,请解释该现象______,写出白磷燃烧的化学方程______.

(3)通常保存少量白磷的方法是______.

考点:燃烧与燃烧的条件化学反应方程式的书写文字表达式物质的变质物质的保存
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证券是各类记载并代表一定权益的 ( )

A.书面凭证

B.法律凭证

C.收入凭证

D.资本凭证

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选择断路器时,应要求断路器的额定开断电流()断路器开断时所通过的最大短路电流。

A.不大于

B.不小于

C.小于

D.大于

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You really do have to wonder whether a few years from now we’ll look back at the first decade of the 21st century—when food prices spiked, energy prices soared, world population surged, tornados plowed through cities, floods and droughts set records, populations were displaced and governments were threatened by the confluence of it all—and ask ourselves. What were we thinking How did we not panic when the evidence was so obvious that we’d crossed some growth, climate, natural resource and population redlines all at once "The only answer can be denial," argues Paul Gilding, an Australian environmentalist, in a new book called The Great Disruption. "When you are surrounded by something so big that requires you to change everything about the way you think and see the world, then denial is the natural response. But the longer we wait, the bigger the response required."

Gilding cites the work of the Global Footprint Network, an alliance of scientists, which calculates how many "planet Earths" we need to sustain our current growth rates. G. F. N. measures how much land and water area we need to produce the resources we consume and absorb our waste, using prevailing technology. On the whole, says G. F. N. , we are currently growing at a rate that is using up the Earth’s resources far faster than they can be sustainably replenished, so we are eating into the future.

This is not science fiction. This is what happens when our system of growth and the system of nature hit the wall at once. We are now using so many resources and putting out so much waste into the Earth that we have reached some kind of limit, given current technologies. The economy is going to have to get smaller in terms of physical impact.

We will not change systems, though, without a crisis. But don’t worry, we’re getting there. We’re currently caught in two loops: One is that more population growth and more global warming together are pushing up food prices, causing political instability in the Middle East, which leads to higher oil prices, thus to higher food prices and more instability. At the same time, improved productivity means fewer people are needed in every factory to produce more stuff. So if we want to have more jobs, we need more factories. More factories making more stuff make more global warming, and that is where the two loops meet.

But Gilding is actually an eco-optimist. As the impact o the imminent Great Disruption hits us, he says, "our response will be proportionally dramatic, mobilizing as we do in war. We will change at a scale and speed we can barely imagine today, completely transforming our economy, including our energy and transport industries, in just a few short decades. " We will realize, he predicts, that the consumer-driven growth model is broken and we have to move to a more happiness-driven growth model, based on people working less and owning less.

According to Paul Gilding, faced with disastrous evidence, people would()

A. be frightened into rethinking the ways we treat the earth

B. refuse to admit the follies committed by human beings

C. set a redline for population growth and the exploration of nature

D. come up with a response required to cope with the worsening situation

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转录因子DNA结合域常见形式有

A.发夹结构
B.锌指结构
C.碱性亮氨酸拉链
D.碱性螺旋-环-螺旋结构

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在地下水严重超采地区,经县以上人民政府批准,可以划定禁止开采或限制开采区。

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