在C、H、O、Cl、Na五种元素中，请选用其中一种或几种元素写出符

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问题填空题

在C、H、O、Cl、Na五种元素中，请选用其中一种或几种元素写出符合下列要求的化学式各一个：

（1）能与血红蛋白结合的有毒气体______；

（2）用于除铁锈的酸______；

（3）常见的干燥剂______；

（4）烹饪食物时常用的调味剂______；

（5）我国“西气东输”工程输送的气体______．

答案

（1）一氧化碳是能与血红蛋白结合的有毒气体，其化学式为：CO．

（2）铁锈的主要成分是氧化铁，能与酸反应，根据提供的元素盐酸符合要求，其化学式为：HCl．

（3）氢氧化钠具有吸水性，是常见的干燥剂，其化学式为：NaOH．

（4）氯化钠是烹饪食物时常用的调味剂，其化学式为：NaCl．

（5）我国“西气东输”工程输送的气体是天然气，其主要成分是甲烷，其化学式为：CH₄．

故答案为：（1）CO；（2）HCl；（3）NaOH；（4）NaCl；（5）CH₄．

阅读理解

Maybe ten-year-old Elizabeth put it best when she said to her father,“But,Dad,you can’t be healthy if you’re dead?”

Dad,in a hurry to get home before dark so he could go for a run,had forgotten to wear his safety belt——a mistake 75% of the US population make every day.The big question is why.

There have been many myths about safety belts ever since their first appearance in cars some forty years ago.The following are three of the most common.

Myth Number One:It’s best to be“thrown clear”of a serious accident.

Truth:Sorry,but any accident serious enough to “throw you clear”is also going to be serious enough to give you a very bad landing.And chances are you’ll have traveled through a windshield(挡风玻璃)or door to do it.Studies show that chances of dying after a car accident are twenty-five times greater in cases where people are“thrown clear.”

Myth Number Two:Safety belts“trap”people in cars that are burning or sinking in water.

Truth:Sorry again,but studies show that people knocked unconscious(昏迷)due to not wearing safety belts have a greater chance of dying in these accidents,People wearing safety belts are usually protected to the point of having a clear head to free themselves from such dangerous situations,not to be trapped in them.

Myth Number Three:Safety belts aren’t needed at speeds of less than 30 miles per hour(mph).

Truth:When two cars traveling at 30 mph hit each other,an unbelted driver would meet the windshield with a force equal to diving headfirst into the ground from a height of 10 meters.

小题1:Why did Elizabeth say to her father,“But Dad,you can’t be healthy if you’re dead”?

A．He didn’t have his safety belt on.

B．He was running across the street.

C．He was driving at great speed

D．He didn’t take his medicine on time.小题2:The reason Father was in a hurry to get home was that he____.

A．wasn’t feeling very well

B．wanted to take some exereise

C．hated to drive in the dark

D．didn’t want to be caught by the police小题3:According to the text,to be “thrown clear”of a serious accident is very dangerous

because you_____.

A．may be knocked down by other cars

B．may get caught in the car door