如表是小妮同学用多种方法来鉴别物质的情况,其中完全正确的是______ 需鉴别物质 分别取样后所加试剂或方法 方法1 方
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如表是小妮同学用多种方法来鉴别物质的情况,其中完全正确的是______
需鉴别物质 | 分别取样后所加试剂或方法 | ||
方法1 | 方法2 | ||
A | 硝酸铵和氢氧化钠 | 加适量水溶解后测温度变化 | 加熟石灰研磨并闻气味 |
B | 氧气和氮气 | 插入带火星的木条 | 闻气味 |
C | 木炭粉末和氧化铜粉末 | 稀硫酸 | 加水溶解 |
D | 黄铜和黄金 | 互相刻划,比较硬度 | ______ |
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yewei925 共回答了17个问题
|采纳率94.1%- 解题思路:A、根据硝酸铵和氢氧化钠溶于水溶液温度的变化和铵盐的检验方法分析;
B、根据氮气和氧气都是无色无味的气体进行分析;
C、根据氧化铜、木炭的化学性质和溶解性进行分析;
D、根据黄金和黄铜硬度、化学性质分析.A、硝酸铵和氢氧化钠加水溶解后,温度明显下降的是硝酸铵,温度明显升高的是氢氧化钠,现象不同,可以鉴别;加入熟石灰研磨后,有刺激性气味的气体生成的是硝酸铵,无现象的是氢氧化钠,现象不同,可以鉴别,符合题意.、故A正确;
B、带火星的木条在氧气中会燃烧更旺,在氮气中会熄灭,现象不同,可以鉴别;氮气和氧气都是无色无味的气体,现象相同,不能鉴别,不符合题意.故B错误;
C、木炭和硫酸不会反应,氧化铜和硫酸反应生成蓝色溶液,现象不同,可以鉴别;但是氧化铜、木炭都不会溶于水中,现象相同,不能鉴别,不符合题意.故C错误;
D、黄金和黄铜的硬度不同,互相刻划,比较硬度,可以鉴别;黄铜中的锌能与盐酸反应生成气泡,金不能与盐酸反应,可以用稀盐酸鉴别.
故选:A.D补充:加稀盐酸.点评:
本题考点: 物质的鉴别、推断;常见气体的检验与除杂方法;金属的化学性质;酸、碱、盐的鉴别.
考点点评: 该题主要考查了常见物质间的反应,通过明显的不同的实验现象达到鉴别物质的目的. - 1年前
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- 6氢氧化铁的颜色在水中和酸中的溶解性怎么写?硫酸钡的颜色在水中和酸中的溶解性怎么写?
- 7繁分数怎么解?请举例说明.
- 8with the hope of 和 in the hope of的区别
- 9他给我一个苹果来换一个梨翻译成英语句子
- 10如图①,AB为⊙O的直径,C为⊙O上一点,过C点的切线CE垂直于弦BD于点E,连BC.
- 11征集一些形容人发财、有财运的词语、成语、俗语、诗句、对联等,越多越好
- 12如图所示,AB=DE,BC=EF,AF=CD.求证:AB∥DE,BC∥EF.
- 13上面一个淮,下面一个十,是什么字
- 14求由方程x^3+y^3-3xy=0所确定的隐函数y=(x)的导数
- 15为什么说微生物对碳源的利用具有选择性