问题 推断题

(3分)现有木炭、铁、一氧化碳、氧化铜、氧化铁、硫酸铜溶液五种物质,它们之间发生的反应,可用“A+B→C+D”表示。

(1)若A为单质,A与B在高温下反应,可观察到固体粉末由黑色逐渐变红,该反应的化学方程式为     

(2)若A为气体化合物,A与B在高温下反应,可观察到固体粉末由红色逐渐变黑,则B是     (填化学式)。

(3)若A为单质,与B在常温下反应,固体表面有红色物质生成,则反应的化学方程式为     

答案

(1)C+2CuO2Cu+CO2↑ (2)Fe2O3(3)Fe+CuSO4= FeSO4+Cu

题目分析:(1)木炭、铁、一氧化碳、氧化铜、氧化铁、硫酸铜溶液中两种物质高温下相互发生反应,生成红色粉末,可判断为高温下碳粉还原氧化铜粉末的反应,生成的红色粉末为铜粉。

(2)物质中的两种高温下相互发生反应,观察到固体粉末由红色逐渐变黑,可判定是高温下氧化铁粉末被还原成黑色的铁粉,A为气体化合物则A为一氧化碳,B为氧化铁。

(3)A为单质,则是木炭或者铁,和其余物质常温下发生反应,固体表面有红色物质生成,则是铁在常温下和硫酸铜溶液发生反应生成单质铜的反应。

点评:这类题目考察的是学生在平时的学习过程中对常见的重要化学反应的熟悉,考查相对综合,是学生能力提升的较好选择。

计算题
问答题

(46) History tells us that in ancient Babylon, the cradle of our civilization, the people tried to build a tower that would reach to heaven. But the tower became the tower of Babel, according to the Old Testament, when the people were suddenly caused to speak different languages. In modern New York City, a new tower, that of the United Nations Building, thrusts its shining mass skyward. (47) But the realization of the UN’s aspirations—and with it the hopes of the peoples of the world—is threatened by our contemporary Babel: about three thousand different languages are spoken throughout the world today, without counting the various dialects that confound communication between peoples of the same land.

In China, for example, hundreds of different dialects are spoken; people of some villages have trouble passing the time of day with the inhabitants of the next town. In the new African state of Ghana, five million people speak fifty different dialects. In India more than one hundred languages are spoken, of which only fourteen are recognized as official. To add to the confusion, as the old established empires are broken up and new states are formed, new official tongues spring up at an increasing rate.

In a world made smaller by jet travel, man is still isolated from many of his neighbors by the Babel barrier of multiplying languages. Communication is blocked daily in scores of ways. Travelers find it difficult to know the peoples of other nations. Scientists are often unable to read and benefit from the work being carried on by men of science in other countries. (48) The aims of international trade, of world accord, of meetings between nations, are blocked at every turn; the work of scholars, technologists, and humanists is handicapped. Even in the shining new tower of the United Nations in New York, speeches and discussions have to be translated and printed in the five official UN language—English, French, Spanish, Russian and Chinese. Confusion, delay, suspicion, and hard feelings are the products of the diplomatic Babel.

The chances for world unity are lessened if, in the literal sense of the phrase, we do not speak the same language. (49) We stand in dire need of a common tongue, a language that would cross national barriers, one simple enough to be universally learned by travelers, businessmen, government representatives, scholars, and even by children at school.

Of course, this isn’t a new idea. Just as everyone is against sin, so everyone is for a common language that would further communication between nations. (50) What with one thing and another—our natural state of drift as human beings, our rivalries, resentments, and jealousies as nations—we have up until now failed to take any action. I propose that we stop just talking about it, as Mark Twain said of the weather, and do something about it. We must make the concerted, massive effort it takes to reach agreement on the adoption of a single, common auxiliary tongue.

(47) But the realization of the UN’s aspirations—and with it the hopes of the peoples of the world—is threatened by our contemporary Babel: about three thousand different languages are spoken throughout the world today, without counting the various dialects that confound communication between peoples of the same land.