问题 填空题

燃烧是人类最早利用的化学反应之一.

(1)生活中,人们常常利用燃料燃烧反应产生的能量来做饭、取暖.下列有关说法正确的是______.

A.化学反应过程中都会发生放热现象

B.在化学反应中只有燃烧反应才能放出热量

C.在当今社会,人类需要的大部分能量是由化学反应产生的

(2)可燃物燃烧除需要氧气外,还需要满足的条件是______;煤块经粉碎处理后,在空气中燃烧得更快、更充分,这是因为______.

(3)火善用之为福,不善用之为祸.下面是一些常用的灭火方法:

①熄灭液化气灶火焰时,关闭阀门;

②木材着火时,用泡沫灭火器灭火;

③油锅着火时,用锅盖盖灭;

④熄灭酒精灯时,用灯帽盖灭;

⑤房屋着火时,用高压水枪灭火;

⑥森林着火时,将大火蔓延线路前的一片树木砍掉.

请你从灭火原理的角度,选择一种分类标准进行分类.

分类标准:______,包括事例:______.(填序号)

答案

(1)A.化学反应过程中,有些是放热的,例如铁在氧气中燃烧,有些是吸热的,例如高温条件下,碳和二氧化碳的反应;该选项叙述不正确;

B.在化学反应中不只是燃烧反应才能放出热量,例如缓慢氧化不是燃烧反应,反应过程中是放热的;该选项叙述不正确;

C.在当今社会,人类需要的大部分能量是由化学反应产生的;该选项叙述正确.

故填:C.

(2)可燃物燃烧除需要氧气外,还需要满足的条件是温度达到可燃物的着火点;煤块经粉碎处理后,增大了煤和氧气的接触面积,在空气中燃烧得更快、更充分.

故填:温度达到可燃物的着火点;增大了煤与氧气的接触面积.

(3)①熄灭液化气灶火焰时,关闭阀门,灭火方法属于移走可燃物;

②木材着火时,用泡沫灭火器灭火,灭火方法属于隔绝氧气;

③油锅着火时,用锅盖盖灭,灭火方法属于隔绝氧气;

④熄灭酒精灯时,用灯帽盖灭,灭火方法属于隔绝氧气;

⑤房屋着火时,用高压水枪灭火,灭火方法属于降低温度到可燃物的着火点以下;

⑥森林着火时,将大火蔓延线路前的一片树木砍掉,灭火方法属于移走可燃物.

②③④的灭火方法属于隔绝氧气.

故填:隔绝氧气;②③④.

单项选择题
阅读理解

Most American students go to traditional public schools.There are about 88, 000 public schools, all over the US.Some students attend about 3000 independent public schools called charter schools.

Charter schools are self-governing.Private companies operate some charter schools.They are similar in some ways to traditional public schools.They receive tax money just as other public schools do.Charter schools must prove to local or state governments that their students are learning.These governments provide the schools with the agreement called a charter that permits them to operate.

Charter schools are different because they do not have to obey most laws governing traditional public schools.Local, state, or federal governments cannot tell them what to teach.Each school can choose its own goals and decide the ways it wants to reach them.Class size is usually smaller than in traditional public schools.

The Bush Administration strongly supports charter schools as a way to re-organize public schools that are failing to educate students.But some education agencies and unions oppose charter schools.One teachers' union has just made public the results of the first national study comparing the progress of students in traditional schools and charter schools.

The American Federation of Teachers criticized the government's delay in releasing the results of the study, which is called the National Assessment of Educational Progress.Union education experts say the study shows that charter school students performed worse on math and reading tests than students in regular public schools.

Some experts say the study is not a fair look at charter schools because students in those schools have more problems than students in traditional schools.Other education experts say the study results should make charter school officials demand improved student progress.

小题1:If a private company wants to operate a charter school, it must______.

A.try new methods of teaching

B.prove its management ability

C.obey the local and state laws

D.get the government's permission小题2:What's the government's attitude toward charter schools?

A.Doubtful

B.Supportive.

C.Subjective.

D.Optimistic.小题3:What can we learn from the text?

A.More students choose to attend charter schools.

B.Charter schools are better than traditional schools.

C.Students in charter schools are well educated.

D.People have different opinions about charter schools.小题4:It can be interred from the text that ___.

A.charter schools are part of the public education system

B.one-on-one attention should be paid to students

C.the number of charter schools will be limited

D.charter schools are all privately financed