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【简答题】
金属用途广泛，其结构和性质等是化学的重要研究内容。 （1）如图是铝的原子结构示意图。下列说法不正确的是 _______ 。 A．铝原子中的质子数为13 B．在化合物中铝通常显+3价 C．铝是地壳中含量最多的元素 D．铝可作导线是由于它具有良好的导电性 （2）某化学小组用一定量的AgNO 3 和Cu（NO 3 ） 2 混合溶液进行了如图实验，并对溶液A和固体B的成分进行了分析和研究。 【提出问题】溶液A中的溶质可能有哪些？ 【做出猜想】 ① 只有Zn（NO 3 ） 2 ② Zn（NO 3 ） 2 、AgNO 3 ③ Zn（NO 3 ） 2 、Cu（NO 3 ） 2 ④ Zn（NO 3 ） 2 、Cu（NO 3 ） 2 、AgNO 3 【交流讨论】不合理的猜想是 _______ （填标号），其理由是 _______ 。 【实验探究】若猜想①成立，通过以下实验可确定固体B的成分，请将下表填写完整。 实验步骤 现象 实验结论 取少量固体B，滴加 _______ 有气泡产生 固体B含有Cu 、Ag和 _ （3）新型材料纳米级 Fe 粉具有广泛的用途，它比普通 Fe 粉更易与氧气反应，其制备工艺流程如图所示： 请回答下列问题： ①纳米级Fe粉在空气中易自燃。实验中通入N 2 的目的是 _______ 。 ②写出H 2 还原FeCl 2 ，置换出铁的化学方程式 _______ 。 ③研究人员发现最后制得的纳米级 Fe 粉样品中混有少量的 FeCl 2 杂质。取样品20g，加入足量的盐酸，生成氢气 0.7 g。请计算该样品中单质 Fe 的质量分数（请写出计算过程）。 _______
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举一反三
【单选题】Alienation is an ambiguous concept with elusive meanings. Which one of the following feelings is not the common variant of alienation?
A.
The feeling that one has no control over one's fate.
B.
The sense of aimlessness in life.
C.
The sense of disillusionment.
D.
The sense of solitude and isolation in social realtions.
【单选题】根据李嘉图的政府债务观点,消费者会将当前的减税看做以下哪一项的增加:
A.
他们的财富
B.
他们当前与未来预期收入的总数
C.
伴随着未来税收增加的当前可支配收入
D.
公共储蓄
【简答题】b. Which concept of probability did you use to make this estimate? classical emirpical or subjective
【单选题】Juanita decided to study the differences among students who choose different majors. Everyone in her study, however, has chosen sociology as a major. Which one of the following can be said about her c...
A.
She needs to study more people.
B.
She can go ahead and do her study relating the two variables.
C.
She really has only one concept.
D.
One of her variables isn’t really a variable because it has only one attribute.
E.
It is not a major.
【单选题】Which one of the following best describes the concept of erosion?
A.
expenses that have already been incurred and cannot be recovered
B.
change in net working capital related to implementing a new project
C.
the cash flows of a new project that come at the expense of a firm's existing cash flows
D.
the alternative that is forfeited when a fixed asset is utilized by a project
E.
the differences in a firm's cash flows with and without a particular project
【简答题】According to the first paragraph, which of the following sentences is INCCORECT? A. In Ancient Rome, Cicero described gratitude as the mother of all virtues. B. Thomas Brown defined gratitude as “that...
【单选题】The concept of garbage-in-garbage-out (GIGO) relates to which information quality attribute?
A.
Timeliness
B.
Location
C.
Form
D.
Authority
【简答题】b. Which concept of probability did you use to make this estimate? classical empirical or subjective
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