问题 填空题

(14分)(1)砷及其化合物有毒,如砒霜(As2O3)有剧毒,环境监测和法医学分析砒霜中毒的反应原理:As2O3 + 6Zn + 12HCl = 6ZnCl2 + 2AsH3↑+ 3H2O,

反应中氧化剂是           ,氧化产物是          

被氧化的元素是    ,还原产物与氧化剂的物质的量比      ,电子转移总数是        

(2)已知硫酸锰(MnSO4)和过硫酸钾(K2S2O8)两种盐溶液在银离子催化下可发生氧化还原反应,生成高锰酸钾、硫酸钾和硫酸。

①请写出并配平上述反应的化学方程式:

                                                              

②若该反应所用的硫酸锰改为氯化锰(MnCl2),当它跟过量的过硫酸钾反应时,除有高锰酸钾、硫酸钾、硫酸生成外,其他的生成物还有                   

答案

(1) As2O3  ;ZnCl2;   Zn  ;  2 :1  ;  12e 

(2)① 2MnSO4 + 5K2S2O8 + 8H2O="===" 2KMnO4 + 4K2SO4 + 8H2SO4

②Cl2(答HClO或HClO3也给分)(2分)

(1)反应中As的化合价从+3价降低到-3价,得到6个电子,所以As2O3是氧化剂,还原产物是AsH3,则还原产物与氧化剂的物质的量比2︰1;锌的化合价从0价升高到+2价,失去2个电子,所以Zn是还原剂,被氧化的元素是锌,氯化锌是氧化产物转移电子是12个。

(2)①Mn的化合价从+2价升高到+7价,失去5个电子。S元素的化合价从+7价降低到+6价,得到1个电子,所以还原剂和氧化剂的物质的量之比是5︰2,因此方程式为2MnSO4 + 5K2S2O8 + 8H2O="===" 2KMnO4 + 4K2SO4 + 8H2SO4

②由于氯离子也能被氧化,所以生成物还有氯气。

选择题
阅读理解

With the rapid social development, the Internet now provides social networks that include online movies and videos.The major television networks have much less control over your mind and their broadcasts for entertainment and, more importantly, advertising.It has long been known that television’s audience will spend more time on the Internet than watching TV.People have found another means of entertainment by going to websites which seem to satisfy their specific interests more completely.This isn’t very good news for the television networks.

The influence of people using DVRs (Digital Video Recorder) also has led to fewer and fewer viewers watching television commercials.Market research indicates the effectiveness of TV ads is getting weaker as a result.Many DVR owners are fast forwarding and skipping television commercials.With viewers now spending an average of four times longer on the Internet and more viewers avoiding commercials, this trend isn’t good for television’s advertising revenues(收益).

Major TV advertisers know full well that their advertising dollars on TV aren’t as an effective investment as they once were.The major players in advertising have been moving towards the Internet as a serious alternative means of advertising.

For thousands of people involved in Internet marketing, it’s history-making to share the revenue that previously all went to major television networks.There’s already a group of Internet marketers being paid a larger amount of advertising revenue.These are everyday people that work usually from home on their own.Advertisers can direct their advertising to websites where viewer types are more likely to be interested in their product or service.

The development of the Internet and its role and change in our lives cannot be compared to any other form of media created throughout the history of mankind.

小题1:People are going to websites for entertainment because _______.

A.they’d like to follow the last trend

B.there are fewer commercials

C.there are more movies and videos

D.they can choose what meets their particular needs小题2:We can learn from the second paragraph that ______.

A.viewers are bored with television commercials

B.the television viewing time should be limited

C.many television commercials are of poor quality

D.there are more commercials on DVRs than on TV小题3:It can be inferred from the passage that _____.

A.people spend time on the Internet mainly for entertainment

B.most people prefer to work at home nowadays

C.the Internet will attract more and more advertisers

D.the appearance of TV changed our lives小题4:The passage mainly tells us ________.

A.the rapid social development

B.the fast development of the Internet advertising

C.the way to advertise on the Internet

D.the influence of television commercials