问题 推断题

(6分)物质A~F都是初中化学中的常见物质,它们有如图所示的转化关系。回答下列问题: 

(1)若E为不溶物,A与F能发生反应,则A、D的化学式为:A       、D           

B+C反应的化学方程式:                    。 

(2)若D为密度最小的气体,F为红色固体,则C、F的化学式为:C        、F         

A +B反应的化学方程式:                                 

答案

(1)CO2;H2O;Ca(OH)2+Na2CO3=CaCO3↓+2NaOH

(2)CuSO4;Cu;Fe+H2SO4=FeSO4+H2↑(合理答案军给分)

题目分析:(1)若E为不溶物,A与B反应生成沉淀,假设A是二氧化碳,B是氢氧化钙,则生成的E是碳酸钙,D是水,若C是碳酸钠,B、C反应生成碳酸钙和氢氧化钠;A与F能发生反应,即二氧化碳与氢氧化钠反应,则A、D的化学式为:A:CO2;D:H2O;B+C反应的化学方程式为:Ca(OH)2+Na2CO3=CaCO3↓+2NaOH。

(2)若D为密度最小的气体,则D是氢气,F为红色固体,F可能是铜,假设A是稀硫酸,B是铁,则D是氢气,E是硫酸亚铁;设C是硫酸铜,则铁和硫酸铜反应,生成铜和硫酸亚铁,则C、F的化学式为:C:CuSO4;F :Cu;A +B反应的化学方程式:Fe+H2SO4=

FeSO4+H2↑。

点评:本题给出的信息较少,符合这些反应的物质也较多,解题的关键是假设一些符合反应条件的物质信息,根据反应的过程,合理的推断。

阅读理解

Researchers have announced the result of two studies on the health effects of the drug aspirin(阿斯匹林). One study shows aspirin can sharply reduce the chance that a healthy, older man will suffer from a heart attack.

The study offered two new results from earlier findings. It said taking one aspirin pill every other day helped only healthy men over the age of fifty. It also said aspirin gave the greatest protection against heart attacks to men with low blood cholesterol(胆固醇) levels.

Earlier in the United States began a major aspirin study in the early 1980s. it included 22,000 healthy men doctors. All were between the ages of forty and eighty-four. More than 11,000 of the doctors took a harmless pill that contained no drug. The men did not know which kind of pill they were taking.

The doctors who took aspirin suffered 44% fewer heart attacks than those taking the harmless pill. 139 men who took aspirin suffered from heart attacks. Ten of them died. 239 men who didn’t take aspirin suffered from heart attacks. Twenty-six of them died.

The researchers said the doctors’ study provides clear proof that taking aspirin can prevent a first heart attack in healthy, older men. They said ,however, the result does not mean every man over the age of fifty should take aspirin. They said aspirin couldn’t help men who do not eat healthy foods, who smoke cigarettes and who are fat. The researchers said men who think they would be helped by taking aspirin should talk with their doctors first.

小题1: The passage tells us that the new use of aspirin is___________.

A.to treat heart disease.

B.to reduce pain while one suffers from a heart attack.

C.to help old people to be more healthy.

D.to reduce the chance of a heart attack in old men.小题2:Aspirin can help those who___________.

A.work as doctors

B.are under 40 years old

C.are fat and smoke cigarettes

D.are older and healthy小题3:From the experiment we can conclude that about _________ of people who suffered from heart attacks without aspirin died.

A.7%

B.11%

C.19%

D.44%

单项选择题