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问题 选择题

将一定的、合金置于水中，结果合金完全溶解，得到20mL、PH=14的溶液，然后用1mol/L的盐酸滴定至沉淀最大时，消耗40mL盐酸。原合金中的物质的量（   ）

A．0．01mol

B．0．02mol

C．0．03mol

D．0．04mol

答案

答案：D

题目分析：由题意知涉及的反应为：2Na+2H2O=2NaOH+H2↑ 2Al+2NaOH+2H2O=2NaAlO2+3H2↑ HCl + NaOH="NaCl" + H2O  NaAlO2+ HCl+H2O=Al(OH)3↓+NaCl，当沉淀达最大值时，溶液为NaCl溶液，根据电荷守恒得n(Na+)=n(Cl-)，根据原子守恒得n(Na)=n(HCl)=0．04mol，选D。

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单项选择题

Part 4


Questions 26-45


·Read the following article and choose the best word for each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.

iPhone Left in Hot Car for Three Hours


The normally peaceful suburban town of Winnetka is still reeling following the news Monday (26) a local resident, whose name is being (27) by police pending a full investigation, left an iPhone unattended for more than three hours in a car (28) in the hot sun.
"Responding to calls from (29) . passersby, who observed the iPhone sitting in a vehicle in the parking (30) of the Westfield Shopping Center, police arrived on the (31) at approximately 4 p.m. and immediately intervened to save the device," said Winnetka police chief Douglas Blaine. "Security cameras have shown that the iPhone had been in the car— with the doors (32) and the windows rolled (33) —since 1 p.m. Due to the tragic and highly emotional (34) of this case, we cannot say any (35) at this time."

A. about B. withC. forD. to

According to official police records, two officers forcibly (36) into the car at 4:07 p.m. and found the iPhone (37) face down on the dashboard. The iPhone at first showed no (38) of life, but after a tense few seconds, officers were able to wake it and get it to (39) to a series of simple touch commands. Police said that if the iPhone were left in the extreme (40) for any longer, it could have died.
The iPhone was rushed by ambulance to a nearby Apple facility for careful (41) .Miraculously, no damage to its memory, screen, or wireless capabilities was reported.
Upper-middle-class suburbanites from all over the North Shore area have reacted to the near-tragedy with an unprecedented outpouring of (42) . Hundreds of cards and letters have come streaming in, and local talk radio shows have been flooded (43) calls demanding that the iPhone’s (44) be prosecuted. Many have come forward offering to take the iPhone into their custody, and still (45) have donated free downloads, ringtones, and MP3s to the victimized object.
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