问题 填空题

物质的用途与其性质密切相关.

(1)做馒头发酵面团时,会产生乳酸等有机酸,蒸馒头前需加入适量的纯碱或小苏打等碱性物质,它们相互作用产生了______气体,使蒸出的馒头疏松多孔;若加入的碱性物质过多,可向面团或蒸锅中添加的少许酸性厨房调味料是______,以免蒸出的馒头口味涩且发黄.

(2)浓硫酸是无色粘稠液体,有吸水性,在化学实验中常用它作干燥剂,但日常生活中却很少用它作除湿剂.原因是______.

(3)生石灰常用作食品干燥剂,原因是(用化学方程式表示)______.

(4)人的胃液里含有胃酸,若胃酸分泌过多会引起胃病.服用“胃舒平”(主要成分是氢氧化铝)可缓解病痛.则该药用于治疗的化学原理是(用化学方程式表示)______.

(5)建筑工地的工人下班前,通常在用剩的石灰浆上覆盖一层沙土,以便第二天使用,原因是(用化学方程式表示)______.

答案

(1)乳酸等有机酸能与纯碱或小苏打等碱性物质反应产生二氧化碳气体,使蒸出的馒头疏松多孔;若加入的碱性物质过多,可向面团或蒸锅中添加的少许酸性厨房调味料食醋,以反应掉过多的碱性物质,以免蒸出的馒头口味涩且发黄.

(2)浓硫酸有腐蚀性,故尽管它有吸水性,在化学实验中常用它作干燥剂,但日常生活中却很少用它作除湿剂.

(3)生石灰能与水反应生成氢氧化钙,常用作食品干燥剂,反应的化学方程式为:CaO+H2O═Ca(OH)2

(4)“胃舒平”(主要成分是氢氧化铝)与胃液中的盐酸反应生成氯化铝和水,可缓解病痛,反应的化学方程式为:.

(5)石灰浆的主要成分是氢氧化钙,能与空气中的二氧化碳反应生成碳酸钙而变质,反应的化学方程式为:CO2+Ca(OH)2═CaCO3↓+H2O.

故答案为:(1)二氧化碳;食醋;(2)浓硫酸有腐蚀性;(3)CaO+H2O═Ca(OH)2;(4)Al(OH)3+3HCl═AlCl3+3H2O;(5)CO2+Ca(OH)2═CaCO3↓+H2O.

阅读理解

American beekeeping operations have been hit hard by what scientists call Colony Collapse Disorder. Almost half of their worker bees have disappeared during the past season. C.C.D. has also been reported in Israel, Europe and South America. Bees fly away from the hive and never return. Sometimes they are found dead; other times they are never found. Many crops and trees depend on pollination (授粉) by bees to help them grow.

A new report says virus may be at least partly responsible for the disorder in honey bee colonies in the United States. This virus is called Israeli Acute Paralysis Virus. It was first identified in Israel in 2004. Ian Lipkin at Columbia University in New York and a team reported the new findings in Science magazine. Doctor Lipkin says the virus may not be the only cause. He says it may work with other causes to produce the collapse disorder.

The team found the virus in colonies with the help of a map of honey bee genes that was published last year. They examined thirty colonies affected by the disorder. They found evidence of the virus in twenty – five of them, and in one healthy colony. The next step is further testing of healthy hives.

The researchers suggested that the United States may have imported the disorder in bees from Australia. They say the bees may carry the virus but not be affected.

The idea is that unlike many American bees, the ability of Australian bees to fight disease has not been hurt by the varroa mite. This insect attacks honey bees, which could make the disorder more likely to affect a hive. Australian bee producers reject these suspicions.

And some researchers suspect that bee production in the United States is down mainly because of the weather. Honey bees gather nectar(花蜜) from flowers and trees. The sweet liquid gives them food and material to make honey. But cold weather this spring in the Midwest reduced the flow of nectar in many flowers. Many bees may have starved. Dry weather in areas of the country could also be playing a part.

Wayne Esaias is a NASA space agency scientist who keeps bees in his free time. He lives in central Maryland, where he has found that flowers are blooming a month earlier than they did in 1970, which may be partly responsible for the disorder. Wayne Esaias is organizing a group of beekeepers to document nectar flow around the country.

小题1: What is the author’s attitude to the causes of the bee disorder?

A.critical

B.neutral

C.supportive

D.negative小题2: What is the passage mainly about?

A.American beekeeping industry has been strongly influenced by the bee disorder.

B.Studies are being carried out on the causes of the bee disorder, but questions remain.

C.How the causes of the bee disorder in U.S have been found.

D.The bee production in U.S is down.小题3: How many possibilities may be involved in the bee disorder according to the passage?

A.Three

B.Four

C.Five

D.Six小题4:We can infer that         from the passage.

A.Israeli acute paralysis virus should be responsible for the disorder.

B.The solution to the disorder will be found eventually.

C.American bees are more likely to defend themselves against hurt from other insects than Australian ones.

D.Many crop and plant production in U.S may be influenced by the bee disorder.

单项选择题