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【简答题】
为验证二氧化碳和氢氧化钠溶液确实能发生化学反应,两个化学兴趣小组的同学进行了如下探究活动. (1)第一小组:小莉同学设计了如右图所示实验装置,集气瓶中充满二氧化碳气体,滴管中吸入了氢氧化钠溶液,集气瓶中的气球通气管与外界空气相通. 实验步骤 实验现象 实验结论 挤压滴管橡胶胶帽,使氢氧化钠溶液滴入集气瓶中. 气球逐渐变大 二氧化碳和氢氧化钠溶液确实发生了化学反应 同组的小对此提出质疑,他将上述实验滴管中的氢氧化钠溶液换成等体积的水,然后 再重复完成实验,观察到现象是气球也变大但比小莉做的实验中的气球小.补充这一实 验的原因是______. (2)第二小组:小对实验装置做了如右图改进.集气瓶中充满二氧化碳气体,气球通 气管与外界空气相通,分液漏斗A中装有氢氧化钠溶液.分液漏斗B中装有另一种试 剂. 步骤一:打开分液漏斗A的活塞,使氢氧化钠溶液流入集气瓶中. 现象:气球逐渐变大. 步骤二:打开分液漏斗B的活塞,使______溶液流入集气瓶中. 现象:______,产生这一现象的化学反应方程式是______. 结论:二氧化碳和氢氧化钠溶液可以反应,该反应的化学方程式是______. (3)对于现象不明显的化学反应,上述两组同学的实验是分别从反应物和生成物两个方面进行的探究验证,其所利用的原理是不同的. ①第一组是通过实验证明______验证化学反应发生了; ②第二组是通过实验证明______验证化学反应发生了.
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【单选题】Questions 1
A.
He set a record by swimming to and from an island.
B.
He celebrated his ninth birthday on a small island.
C.
He visited a prison located on a faraway island.
D.
He swam around an island near San Francisco.
【单选题】在OSI参考模型中,属于传输层的协议是()。
A.
TELNET
B.
SNMP
C.
TCP
D.
ICMP
【判断题】Questions 1-5 is based on the record you have just heard. 1.The Green Club is an enviromental group.
A.
正确
B.
错误
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A.
TELNET
B.
TCP
C.
UDP
D.
SSL
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【单选题】1-14 (Objectives 1-1, 1-3, 1-5) The following questions deal with audits by CPA firms. Choose the best response. Which of the following best describes why an independent auditor is asked to express an...
A.
(1) It is difficult to prepare financial statements that fairly present a company’s financial position, operations, and cash flows without the expertise of an independent auditor.
B.
(2) It is management’s responsibility to seek available independent aid in the appraisal of the financial information shown in its financial statements.
C.
(3) The opinion of an independent party is needed because a company may not be objective with respect to its own financial statements.
D.
(4) It is a customary courtesy that all stockholders of a company receive an independent report on management’s stewardship of the affairs of the business.
【简答题】Answer the following questions according to passage 1What is the best timing for sending out an invitation to an evening reception?
【多选题】下面协议中属于传输层协议的是()。
A.
UDP
B.
Telnet
C.
TCP
D.
http
【简答题】我们一般用多大的帧速率?
【单选题】Choose the best answer for each of the following questions. 1. What did the author do before she became an apprentice to an education journalist?
A.
She was a salesperson.
B.
She was a writer.
C.
She was a journalist.
D.
She was an editor.
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