问题 填空题

某银白色金属M在日常生产和生活中应用最广泛,M的某合金材料是建筑工程中不可缺少的建材;M在右图所示的反应中,可得到A、B、C、D四种产物,A为黑色固体,D的组成中M与Cl的原子个数比为1:3.

(1)A的化学式为(用M的真实元素符号表示,后同)______,A在物质分类中属于______(选填代号字母);a.单质b.酸c.碱d.盐e.有机物f.氧化物h.混合物

(2)物质B的化学式为______;M与Cu、(H)三者在金属活动性顺序中由强到弱的排序为:______;

(3)写出下列指定反应的化学方程式:反应③:______;反应④:______D+AgNO3反应:______.

答案

(1)由于M是日常生产和生活中应用最广泛的金属,所以M的化学式是Fe,A是铁燃烧的产物,所以A是四氧化三铁,该物质属于两种元素组成,其中一种是氧元素的化合物,所以是氧化物;

(2)铁与盐酸反应除生成氢气外还会生成氯化亚铁,化学式为FeCl2,依据金属活动性顺序表可知Fe与Cu、(H)三者在金属活动性顺序中由强到弱的排序为Fe、(H)、Cu;

(3)反应③是铁与硫酸铜生成铜与硫酸亚铁的反应,方程式为:Fe+CuSO4=FeSO4+Cu;反应④为铁与氯气的反应由于D的组成中M与Cl的原子个数比为1:3,所以生成物的化学式为FeCl3,该反应的方程式为:2Fe+3Cl2

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2FeCl3;D+AgNO3反应是氯化铁与硝酸银的反应,其产物是氯化银沉淀和硝酸铁,方程式为:FeCl3+3AgNO3=3AgCl↓+Fe(NO33

故答案为:(1)Fe;f;(2)FeCl2;Fe、(H)、Cu;(3)Fe+CuSO4=FeSO4+Cu;2Fe+3Cl2

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2FeCl3;FeCl3+3AgNO3=3AgCl↓+Fe(NO33

单项选择题
单项选择题

Electronic mail has become an extremely important and popular means of communication.

The convenience and efficiency of electronic mail are threatened by the extremely rapid growth in the volume of unsolicited commercial electronic mail. Unsolicited commercial electronic mail is currently estimated to account for over half of all electronic mall traffic, up from an estimated 7 percent in 2001, and the volume continues to rise. Most of these messages are fraudulent or deceptive in one or more respects.

The receipt of unsolicited commercial electronic mail may result in costs to recipients who cannot refuse to accept such mail and who incur costs for the storage of such mail, or for the time spent accessing, reviewing, and discarding such mail, or for both. The receipt of a large number of unwanted messages also decreases the convenience of electronic mall and creates a risk that wanted electronic mail messages, both commercial and noncommercial, will be lost, overlooked, or discarded amidst the larger volume of unwanted messages, thus reducing the reliability and usefulness of electronic mail to the recipient. Some commercial electronic mail contains material that many recipients may consider vulgar or pornographic in nature.

The growth in unsolicited commercial electronic mail imposes significant monetary costs on providers of Internet access services, businesses, and educational and nonprofit institutions that carry and receive such mail, as there is a finite volume of mail that such providers, businesses, and institutions can handle without further investment in infrastructure. Many senders of unsolicited commercial electronic mail purposefully disguise the source of such mall.

Many senders of unsolicited commercial electronic mall purposefully include misleading information in the messages’ subject lines in order to induce the recipients to view the messages. While some senders of commercial electronic mail messages provide simple and reliable ways for recipients to reject (or ’opt-out’ of) receipt of commercial electronic mall from such senders in the future, other senders provide no such ’opt-out’ mechanism, or refuse to honor the requests of recipients not to receive electronic mail from such senders in the future, or both.

Many senders of bulk unsolicited commercial electronic mail use computer programs to gather large numbers of electronic mail addresses on an automated basis from Internet websites or online services where users must post their addresses in order to make full use of the website or service.

The problems associated with the rapid growth and abuse of unsolicited commercial electronic mall cannot be solved by the government alone. The development and adoption of techno-logical approaches and the pursuit of cooperative efforts with other countries will be necessary as well.

The unwanted e-mail problem can be solved if ().

A. the government takes action

B. a new technology is adopted

C. more people are aware of the problem

D. joint efforts are made and new technology is used