搜题请搜索小程序“爱下问搜题”
问题 选择题

初中化学学习完成后，你简单了解了一些物质的性质，下列区分方法正确的是（　　）

A．区分银和铜，用盐酸

B．区分硬水和软水，加肥皂水搅拌

C．区分N2和CO2，伸入燃烧的木条

D．区分NaCl和KCl，加水溶解

答案

A、在金属活动性顺序中，铜和银都要位于氢的后面，都不与盐酸反应，所以错误．

B、向等量的两种水样中分别加入等量的肥皂水，振荡，泡沫多的是软水，泡沫少的是硬水，所以正确．

C、氮气和二氧化碳均不支持燃烧，都能使燃烧的木条熄灭，所以错误．

D、氯化钠和氯化钾都能溶解于水，水溶液都无色，溶解时都无明显的吸热、放热现象，无法区分，所以错误．

故选B．

解答题

从4名男生甲、乙、丙、丁，三名女生A、B、C中抽出3名同学参加学校组织的数学竟赛，要求男，女生都有同学参加，问：（1）男生甲参加比赛有多少种情况；（2）男生甲参加比赛的概率．
查看答案
填空题

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.
查看答案