问题 填空题
3.82升=______立方分米
40平方厘米=______平方分米
3吨50千克=______吨
4
5
12
小时=______时______分.
答案

(1)3.82升=3.82立方分米;

(2)40平方厘米=0.4平方分米;

(3)3吨50千克=3.05吨;

(4)4

5
12
小时=4时25分.

故答案为:3.82,0.4,3.05,4,25.

单项选择题

Prince Klemens Von Metternich, foreign minister of the Austrian Empire during the Napoleonic era and its aftermath, would have no trouble recognizing Google. To him, the world’s most popular web-search engine would closely resemble the Napoleonic France that in his youth humiliated Austria and Europe’s other powers. Its rivals--Yahoo !, the largest of the traditional web gateways, eBay, the biggest online auction and trading site, and Microsoft, a software empire that owns MSN, a struggling web portal--would look a lot like Russia, Prussia, and Austria. Metternich responded by forging an alliance among those three monarchies to create a "balance of power" against France. Google’s enemies, he might say, ought now to do the same thing.

Google announced two new conquests on August 7th. It struck a deal with Viacom, an "old" media firm, under which it will syndicate video clips from Viacom brands such as MTV and Nickelodeon to other websites, and integrate advertisements into them. This makes Google the clear leader in the fledgling but promising market for web-video advertising. It also announced a deal with News Corporation, another media giant, under which it will provide all the search and text-advertising technology on News Corporation’s websites, including MySpace, an enormously popular social-networking site.

These are hard blows for Yahoo! and MSN, which had also been negotiating with News Corporation. Both firms have been losing market share in web search to Google over the past year--Google now has half the market. They have also fallen further behind in their advertising technologies and networks, so that both make less money than Google does from the same number of searches. Sara Rashtchy, an analyst at Piper Jaffray, a securities firm, estimates that for every advertising dollar that Google makes on a search query, Yahoo! makes only 60-70 cents. Last month Yahoo! said that a new advertising algorithm that it had designed to close the gap in profitability will be delayed, and its share price fell by 22% , its biggest-ever one-day drop.

MSN is further behind Google than Yahoo! in search, and its parent, Microsoft, faces an even more fundamental threat from the expansionist new power. Many of Google’s new ventures beyond web search enable users to do things free of charge through their web browsers that they now do using Microsoft software on their personal computers. Google offers a rudimentary but free online word processor and spreadsheet, for instance.

The smaller eBay, on the other hand, might in one sense claim Google as an ally. Google’s search results send a lot of traffic to eBay’s auction site, and eBay is one of the biggest advertisers on Google’s network. But the relationship is imbalanced. An influential recent study from Berkeley’s Haas School of Business estimated that about 12% of eBay’s revenues come indirectly from Google, whereas Google gets only 3% of its revenues from eBay. Worst of all for eBay, Google is starting to undercut its core business. Sellers are setting up their own websites and buying text advertisements from Google, and buyers are using its search rather than eBay to connect with sellers directly. As a result, "eBay would be wise to strike a deep partnership with Yahoo ! or Microsoft in order to regain a balance of power in the industry," said the study’s authors, Julien Decor and Steve Lee, sounding like diplomats at the Congress of Vienna in 1814.

Google will play a decisive role in the market for web-video advertising because of()

A. Google’s new business transaction with Viacom

B. the technology available in Viacom

C. Google’s deal with News Corporation

D. the popularity of a social-networking site

实验题

(16分)为测定碳酸钙纯度(设含杂质SiO2),学生设计了如下几个实验方案。请回答每个方案中提出的问题。

【方案I】

(1)称取碳酸钙样品M g;

(2)加入过量盐酸;

(3)收集并测定生成的气体体积V mL。

问题1:反应结束后,量气管中的显示如右图所示,接下来的操作是:                                   ,读出甲管中液面的读数。

【方案II】

(1)称取碳酸钙样品M g;

(2)用c mol/L 盐酸V mL(过量)溶解样品;

(3)取溶解后的溶液mL,以酚酞作指示剂,用c′ mol/L NaOH溶液滴定,恰好用去V′mL。

问题2:列出本实验中所用到的主要仪器名称(除铁架台及附件、烧杯之外)                                            

问题3:碳酸钙纯度计算公式                                 

问题4:当碳酸钙溶解完全后,少量未溶的SiO2没过滤去,结果得到碳酸钙纯度________   (偏大、偏小或无影响)

【方案Ⅲ】

(1)称取碳酸钙样品M g;

(2)加入足量c mol/L盐酸V mL使之完全溶解;

(3)过滤并取滤液;

(4)在滤液中加入过量c′ mol/L Na2CO3溶液V′mL;

(5)将步骤(4)中的沉淀滤出、洗涤、干燥、称重为M′g。

问题5:此方案中不需要的数据是               (填选项编号)。

A.c、V

B.c′、 V′

C. M

D. M问题6:为减少实验误差,步骤(3)、(5)过滤后都要对沉淀进行洗涤,如果步骤(3)未经洗涤,则测定的碳酸钙的纯度将            (偏大、偏小、无影响,下同);如果步骤(5)未经洗涤,则测定的碳酸钙纯度将           

问题7:判断步骤(4)中Na2CO3溶液是否过量的方法是                         。