问题 填空题

将25gA物质和5gB物质混合加热反应后,测得A物质仍有10g,B物质已经反应完,生成C物质11g,还有一种新物质D.在这个化学反应中,反应物和生成物的质量比依次为m(A):m(B):m(C):m(D)=______.若A、B、C、D的相对分子质量分别为30、20、44、18,则该反应的化学方程式为______.

答案

由题意可知,(25克-10g)A和5克B反应能生成11克C,生成D的质量为:15克+5克-11克=9克,则A、B、C、D四种物质的质量比为:15:5:11:9.

设ABCD四五之前的化学计量数分别是abcd,则有aA:bB:cC:dD=15:5:11:9,则abcd的数值比是2:1:1:2,则该反应的化学方程式为:2A+B=C+2D

故答案为:15:5:11:9;2A+B=C+2D.

选择题
单项选择题

Some of the concerns surrounding Turkey’s application to join the European Union, to be (1) on by the EU’s Council of Ministers on December 17th, are economic--in particular, the country’s relative poverty. Its GDP per head is less than a third of the average for the 15 pre-2004 members of the EU. (2) it is not far off that of Latvia--one of the ten new members which (3) on May 1st 2004, and it is much the same as (4) of two countries, Bulgaria and Romania, which this week concluded (5) talks with the EU that could make them full members on January 1st 2007.

(6) , the country’s recent economic progress has been, according to Donald Johnston, the secretary-general of the OECD, stunning. GDP in the second quarter of the year was 13.4% higher than a year earlier, a (7) of growth that no EU country comes close to (8) . Turkey’s (9) rate has just fallen into single figures for the first time since 1972, and this week the country (10) agreement with the IMF on a new three-year, $10 billion economic program that will help Turkey (11) inflation toward European levels, and enhance the economy’s resilience.

Resilience has not historically been the country’s economic p point. (12) , throughout the 1990s growth oscillated like an electrocardiogram (13) a violent heart attack. This (14) has been one of the main reasons why the country has failed dismally to attract much-needed foreign direct investment. Its stock of such investment is lower now than it was in the 1980s, and annual (15) have scarcely ever reached $1 billion.

One deterrent to foreign investors is due to (16) on January 1st 2005. On that day, Turkey will take away the right of virtually every one of its citizens to call themselves a millionaire. Six zeros will be removed from the face value of the lira (里拉,土耳其货币单位); one unit of the local (17) will henceforth be worth what 1 million are now--ie, about £ 0.53 (0.53 欧元). Goods will have to be (18) in both the new and old lira for the whole of the year, (19) foreign bankers and (20) can begin to look forward to a time in Turkey when they will no longer have to juggle mentally with indeterminate strings of zeros.

20()

A.merchants

B.travelers

C.investors

D.executives