向含有AgNO3、Cu(NO3)2、Zn(NO3)2的混合溶液中加入一定量的铁粉_爱下问搜题

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问题选择题

向含有AgNO₃、Cu(NO₃)₂、Zn(NO₃)₂的混合溶液中加入一定量的铁粉，充分反应后，过滤。则下列情况中可能出现的是

①滤液中有Ag⁺、Cu²⁺、Zn²⁺、Fe²⁺，不溶物为Ag；

②滤液中有Ag⁺、Cu²⁺、Zn²⁺、Fe²⁺，不溶物为Ag、Cu；

③滤液中有Fe²⁺、Zn²⁺，不溶物为Ag、Cu、Zn；

④滤液中有Fe²⁺、Zn²⁺,不溶物为Ag、Cu、Fe

A．①③

B．①④

C．②③

D．②④

答案

答案：B

①、若加入的铁粉量少，只能与部分硝酸银反应生成银，故滤纸上有Ag，滤液中有Ag⁺、Cu²⁺、Zn²⁺、Fe²⁺，故正确；

②、当滤纸上含有银和铜，则滤液中不能含有Ag⁺，因为铜能将银离子置换为银，故错误

③锌比铁活泼，铁不会置换出锌，故错误．

④、当铁加入过量时，能将全部的硝酸银和硝酸铜置换出来，铁粉有剩余，则滤纸上有Ag、Cu、Fe，滤液中有Zn²⁺、Fe²⁺，故正确；

故选B

单项选择题

关于学校健康促进，不包括在内的是

A．学校、家长、社区共同奋斗，为学生提供健康知识

B．其对象应包括大中小学生

C．应以确保其间断性的方式进行

D．创造安全健康的学校环境

E．提供合适的健康服务

填空题

B The Culture Debate in the US:Whose Culture Is This ,Anyway 美国的文化辩论：空间是谁的文化？
Part of the debate about culture revolves around issues of perspective and ownership. Within a nation such (1) the United States—a nation whose cultural heritage includes elements from every corner of the world (2) are a great many perspectives coexisting and intertwining in the cultural fabriC．When we all ask (3) as individuals, "what belongs to me, to my culture " we are rewarded with a spectacular variety of (4) ; in this way, different perspectives and ownership of different cultural traditions enriches everyone. But when we ask " (5) belongs to us, to our culture " we ask a much harder question. Do the people of the (6) States, or of any culturally complex human society, necessarily share common cultural elements If so, who gets (7) decide what those elements are
This debate is a crucial one in many cultures throughout the world (8) . In the US, the debate promises to impact the way we educate our children—that is, (9) manner and shape in which culture reproduces itself—and the way we write our laws. In (10) countries, equally crucial issues are at stake.
For many people, what is at stake is the character (11) US national identity. Hirsch argues that this identity needs to become less culturally fragmented; others, like Walker, (12) that the national character gets its strength from cultural diversity, from the freedom (at home and in (13) ) to celebrate, honor, and reproduce different cultural traditions. Those who take this latter view follow the reasoning (14) Shweder, arguing that we need to accept that there are multiple valid cultural perspectives and that two (15) perspectives can both be valid even though they might contradict one another.
Recognize that the position you (16) in this debate about culture—whatever position you take—is a political one with implications (17) what we should value, what we should praise, what we should accept, what we should teach. When (18) reflect on this debate, when you contribute your own voice to the discussion, try to be (19) of the implications that follow from your position. When you listen to the voices of others, try to (20) with awareness, deciding for yourself what is at stake and how their positions relate to your own.