问题 问答题

空气中的二氧化碳超过正常含量时,会对人体健康产生如下影响:

【提出问题】如何检验空气中二氧化碳的含量以便判断是否会影响人体健康?

【实验探究】

方法一:分别向二氧化碳含量不同的空气中放入燃着的蜡烛.

方法二:分别向二氧化碳含量不同的空气中加入适量的澄清石灰水.

【实验现象】

空气中二氧化碳体积分数0.03%1%5%10%20%
方法一正常燃烧正常燃烧正常燃烧燃烧不旺熄灭
方法二不变浑浊变浑浊变浑浊变浑浊变浑浊
【分析与应用】

(1)上述实验中,方法一所依据的二氧化碳的性质是______;

方法二所依据的反应原理是______(用化学方程式表示).

(2)菜窖中一般会含有较多的二氧化碳,人不能贸然进入.

①菜窖中二氧化碳气体的主要来源是______;

②为确保人体健康不受影响,在进入菜窖前,应对其中的二氧化碳的含量进行检验,有关操作步骤是______.

答案

(1)方法一是向二氧化碳含量不同的空气中放入燃着的蜡烛,观察其燃烧情况,这主要是依据二氧化碳不支持燃烧的性质,方法二向二氧化碳含量不同的空气中加入适量的澄清石灰水,观察变浑浊的情况,这不要是依据二氧化碳能使澄清的石灰水变浑浊的性质,所以本题答案为:二氧化碳不能支持燃烧;CO2+Ca(OH)2=CaCO3↓+H2O;

(2)自然界中二氧化碳的来源主要是动植物的呼吸作用,菜窖中的二氧化碳就主要来自蔬菜的呼吸作用,二氧化碳不能帮助呼吸,含量高时就可能导致人死亡,进入久未开启的菜窖,为防止事故发生,要先做灯火实验,所以本题答案为:①植物的呼吸作用.②做灯火试验,灯火熄灭或燃烧不旺,就不能冒然进入.

单项选择题
单项选择题

On the first Earth Day, the U.S. was a poisoned nation. Dense air pollution blanketed cities like Los Angeles, where smog alerts were a fact of life. Dangerous pesticides like DDT were still in use, and water pollution was rampant—symbolized by raging fires on Cleveland’s Cuyahoga River. But the green movement that was energized by Earth Day— and the landmark federal actions that followed it—changed much of that. Today air pollution is down significantly in most urban areas, the water is cleaner, and even the Cuyahoga is home to fish again.

But if the land is healing, Americans may be sickening. Since World War Ⅱ, production of industrial chemicals has risen rapidly, and the U.S. generates or imports some 19 billion kg of them per day. These aren’t the sorts of chemicals that come to mind when we picture pollution—huge plants spilling contaminated wastewater into rivers. Rather, they’re the molecules that make good on the old "better living through chemistry" promise, appearing in items like unbreakable baby bottles and big-screen TVs. Those chemicals have a, habit of finding their way out of everyday products and into the environment—and ultimately into living organisms. A recent biomonitoring survey found traces of 212 environmental chemicals in Americans—including toxic metals, pesticides, etc. "It’s not the environment that’s contaminated so much," says the director of the Cincinnati Children’s Environmental Health Center. "It’s us."

As scientists get better at detecting the chemicals in our bodies, they’re discovering that even tiny quantities of toxins can have a potentially serious impact on our health—and our children’s future. Chemicals like bisphenol A (BPA) and phthalates—key ingredients in modern plastics—may disrupt the delicate endocrine system. A host of modern ills that have been rising unchecked for a generation—obesity, diabetes, attention-deficit disorder —could have chemical connections. "We don’t give environmental exposure the attention it deserves," says Dr. Philip Landrigan. "But there’s an emerging understanding that kids are uniquely susceptible to environmental hazards."

Washington has been slow to arrive at that conclusion. The Toxic Substances Control Act (TSCA), the 34-year-old vehicle for federal chemical regulation, has generally been a failure. The burden of proving chemicals dangerous falls almost entirely on the government. And the Environmental Protection Agency (EPA) has been able to issue restrictions on only a handful of chemicals and has lacked the power to ban even some dangerous cancer-causing substances.

But change is coming. The Obama Administration is taking a closer look at chemicals. More important, Congress may finally be ready to act. "We can’t permit this assault on our children’s health—and our own health—to continue," says Senator Frank Lautenberg.

According to Senator Frank Lautenberg, ()

A. actions should be taken to protect children from the environmental chemicals

B. more people begin to realize children’s susceptibility to environmental hazards

C. we should give more attention to environmental exposure

D. it’s more important and urgent to protect children’s health