题目

 (1)学校运动会上短跑项目“发令枪”里的火药成分为KClO3、MnO2和红磷,当扣动扳机时,①撞针撞击火药,产生热量使KClO3分解产生O2;②并引燃红磷产生白烟。试分别写这两步反应的化学方程式。 ① ;  ② ,基本反应类型是  。  (2)“84”消毒液可用于灾区防疫,其主要成分是次氯酸钠(NaClO),制取它的化学方程式为2NaOH+XNaClO+NaCl+H2O,则X的化学式为 。求出NaClO中氯元素的化合价并在该化学式中表示出来 。  (3)固体MgH2是氢能源汽车的供能剂,MgH2与水反应生成一种碱Animals are natural resources that people have wasted all through our history. Animals have been killed for their fur and feathers, for food, for sport, and simply because they were in the way. Thousands of kinds of animals have disappeared from the world forever. Hundreds more are on the danger list today. About 170 kinds in the United States alone are considered in danger. Why should people care? Because we need animals. And because once they are gone, there will never be any more. Animals are more than just beautiful and interesting. They are more than just a source of food. Every animal has its place in the balance of nature. Destroying one kind of animal can create many problems. For example, when farmers killed large numbers of hawks(老鹰), the farmers stores of corn and grain were destroyed by rats and mice. Why? Because hawks eat rats and mice. With no hawks to keep down their numbers, the rats and mice multiplied(繁殖) quickly. Luckily, some people are working to help save the animals. Some groups raise money to let people know about the problem. And they try to get the governments to pass laws protecting animals in danger. Quite a few countries have passed laws. These laws forbid the killing of any animals or plants on the danger list. Slowly, the number of some animals in danger is growing.【小题1】Animals are important to us mainly because____. A．they give us a source of foodB．they are beautiful and lovelyC．they keep the balance of natureD．they give us a lot of pleasure【小题2】What has happened to the animals on the earth?A．Hundreds of kinds of animals have disappeared forever.B．Many kinds of animals have died out.C．About 170 kinds of animals have disappeared forever.D．All kinds of animals are in danger.【小题3】Which of the following is NOT true?A．People care much about animals because they need them.B．Once a certain kind of animals is gone forever, there will never be any more.C．Killing all rats and mice may cause some problems.D．People must not kill any animals.【小题4】What can we infer from the fact that quite a few countries have passed laws protecting animals in danger?A．Every person will know the importance of protecting wild animals.B．Animals in danger will not be killed any more.C．The number of some animals in danger will increase.D．Animals in danger will be kept away from people.