2022年小升初典型奥数专题一浓度问题 .pdf

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1、学科：情景数学动漫浓度三角【知识网络】溶度问题包括以下几种基本题型（1）溶剂的增加或减少引起浓度变化。面对这种问题，不论溶剂增加或减少，溶质是始终不变的，据此便可解题。（2）溶质的增加引起浓度变化。面对这种问题，溶质和浓度都增大了，但溶剂是不变的，据此便可解题。（3）两种或几种不同溶度的溶液配比问题。面对这种问题，要抓住 混合前各溶液的溶质和与混合后溶液的溶质质量相等，据此便可解题。【情景故事】溶液的质量溶质的质量溶剂的质量浓度=溶质重量溶液重量溶液重量=溶质重量浓度黄小鸭喝奶茶的故事黄小鸭领着三个鸭弟弟在森林里游玩了半天，感到又渴又累，正好路过了奶牛开的奶茶店。只见店门口张贴着广告：“既甜又

2、浓的奶茶每杯0.3 元。”黄小鸭便招呼弟弟们歇脚，一起来喝奶茶。黄小鸭从奶牛手中接过一杯奶茶，给最小的弟弟老四喝掉61，加满水后给老三喝掉了31，再加满水后，又给老二喝了一半，最后自己把剩下的一半喝完。奶牛开始收钱了，他要求黄小鸭最小的弟弟付出0.3 610.05(元)；老三 0.3 310.1(元)；老二与黄小鸭付的一样多，0.3 210.15(元)。兄弟四个一共付了0.45 元。兄弟们很惊讶，不是说，一杯奶茶0.3 元，为什么多付0.450.3 0.15 元？肯定是奶牛再敲诈我们。不服气的黄小鸭嚷起来：“多收我们坚决不干。”“不给，休想离开。”现在，大家说说为什么会这样呢？【自学指导】浓度

3、问题是围绕溶质、溶剂、溶液及浓度展开的。解题过程中我们要仔细分析题目，分清在变化前后，谁变了，谁没变，紧紧抓住不变量，这是解题的突破口，也是本节重点。第一类：稀释技巧：稀释前溶质重量稀释后溶质重量第二类：稀释技巧：加浓前溶剂重量加浓后溶剂重量第三类：溶液混合和互换技巧：溶质溶液溶质（溶质溶剂）浓度【方法指导】1、“浓度三角”法（改“十字交叉”法。）【解法范例】用浓度为45和 5的两种盐水配制成浓度为30的盐水 4千克，需要这两种盐水各多少千克？浓度问题方法金手指保持浓度：溶质溶剂齐加减增加浓度：加溶质或减溶剂降低浓度：减溶质或加溶剂文档编码:CM9H2D9W10P2 HF8N2N7F10P5

4、ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5

5、 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P

6、5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10

7、P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F1

8、0P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F

9、10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7

10、F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W103 2、权重法我 们把，每份 溶液所占 全部溶 液的 份 数称为 权 重，记为q1，q2，q3，,，qn，我们 知 道qk=nkkmm

11、mmmm321niikmm1。则混合后，溶液的浓度等于，各自溶液的浓度乘以它的权重的和，即：混合后浓度nnqmqmqmqm332211niiiqm1我们可以将纯溶质看成浓度为 100，将纯溶剂看成0。【解法范例】我们把50的盐水 1 千克与 20的盐水 4 千克混合，求混合后溶液浓度？一、简化的方法简化了的方法更容易被人接受和利用。我们先通过几道简单的问题了解一下新的方法。例 1 有浓度为 20的盐水 300克，要配制成 40的盐水，需加入浓度为70的盐水多少克？例 2 将 75的酒精溶液 32 克稀释成浓度为 40的稀酒精，需加入水多少克？用三角形解浓度问题文档编码:CM9H2D9W10P2

12、 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P

13、2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10

14、P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W1

15、0P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W

16、10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9

17、W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D

18、9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10例 3 买来蘑菇 10 千克，含水量为 99，晾晒一会儿后，含水量为98，问蒸发掉多少水份？二、灵活的技巧

19、“解题有法，但无定法”，解题方法的运用要讲究技巧，根据具体题目加以灵活运用，不要生搬硬套，形成定式。例 4 甲容器中有纯酒精11 升，乙容器中有水 15 升，第一次将甲容器中的一部分纯酒精倒入乙容器，使酒精与水混合。第二次将乙容器中的混合液倒入甲容器。这样甲容器中纯酒精含量为62.5，乙容器中纯酒精的含量为40。那么第二次从乙容器中倒入甲容器的混合液是多少升？三、广泛的应用通过前面例题的讲解，我们发现，新的解法利用浓度差的比与重量的比成反比的关系，把题目退到“份数”上考虑，数据也变简化了。这种方法应用较广泛，有些题目适合用这种方法解答。例 5 某班有学生 48 人，女生占全班的37.5，后来又

20、转来女生若干人，这时人数恰好是占全班人数的 40，问转来几名女生？例 6 服装厂出售 6000 件男女服装，男式皮衣件数占男衣的12.5，女式皮衣件数占女衣的25%，男女皮衣件数之和占这批服装件数的1/5。这批服装中男式皮衣有多少件？女式皮衣有多少件？例 7 甲乙两个仓库共存放420 吨货物，甲仓运出的货物相当于余下货物的1/3，乙仓库运出的货物相当于余下货物的1/4，这时两仓库共余下货物327 吨，甲仓原有货物多少吨？乙仓原有货物多少吨？例 8 小明到商店买红、黑两种笔共66 支。红笔每支定价 5 元，黑笔每支定价 9 元。由于买的数量较多，商店就给予优惠，红笔按定价85付钱，黑笔按定价80

21、付钱，如果他付的钱比按定价少付了18，那么他买了红笔多少支？（北京市第14 届迎春杯数学竞赛初赛试题）试一试：水果店购进苹果1000千克，运输途中碰坏了一些，没有碰坏的苹果卖完后，利润率为40%，碰坏的苹果只能降低出售，亏了60%，最后结算时发现总的利润为32%，问：碰坏 _千克苹果。文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10

22、P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F1

23、0P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F

24、10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7

25、F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N

26、7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2

27、N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N

28、2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W105 浓度三角形主要用于解决两种不同浓度糖水混合的问题出一道例题解释一下30%糖水和 1 体积的水混合，浓度为24%，那么再和 1 体积的水混合，浓度为多少引入浓度三角0.3（4）0（1）0.06 0.24 0.24（5）0（1）0.20(6)已知两份液体的浓度（0.3 和 0）和混合后的浓度（0.24）将他们摆出三角形的关系，用两个浓度分别减去混合后的浓度，这两个差之比就是体积的反比

29、，这个就是浓度三角形文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 Z

30、W9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5

31、ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5

32、 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P

33、5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10

34、P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F1

35、0P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10怎样学好浓度问题 6(组图)在浓度问题的解决中，我们

36、经常可以使用“浓度三角”。什么是浓度三角呢？浓度三角就是把混合前后的不同浓度写成一种对称的三角形的形式。实质上是找混合前两种溶液的浓度与混合后溶液浓度的差之比。这种方法简化了复杂的浓度问题，比较容易理解和使用。例 1.在 100 千克浓度为 50%的盐水中，再加入多少千克浓度为5%的盐水就可以配制成浓度为25%的盐水？分析：混合前两种溶液的浓度与混合后溶液的浓度的差之比，与所需数量之比恰好是成反比例关系，即所需溶液重量之比等于浓度差的反比。我们可以写成浓度三角的形式（如下图）更直观地反映三个浓度之间的大小关系。解法一：（50%-25%）（25%-5%）252054 混合前两种溶液的浓度与混合后

37、溶液的浓度的差之比所需浓度 50%的溶液所需浓度5%的溶液 45 100 4 5125（千克）答：再加入 125kg浓度为 5%的盐水。文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2

38、 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P

39、2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10

40、P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W1

41、0P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W

42、10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9

43、W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D

44、9W10P2 HF8N2N7F10P5 ZW9A4H5L9W107 解法二：方程解法分析。既然混合前后三种溶液的浓度是已知的，只要设出加入的5%浓度的盐水是xkg，那么混合后的盐水总量就是（x100）千克。显然，混合前的两种溶液所含的纯盐等于混合后的溶液里的纯盐。解：设再加入 xkg浓度为 5%的盐水。50%盐水里的盐 5%盐水里的盐混合后25%盐水的盐5%x100 50%（x100）25%5%x 5025%x25 250.2x，x125 答：再加入 125kg浓度为 5%的盐水。例 2.40%的盐水与 20%的盐水混合后，要配制成25%的盐水 180 克。求 40%与 20%盐水各需多少克？

45、解法一：（40%-25%）（25%-20%）15531 所需溶液重量之比等于浓度差的反比所需高浓度的溶液所需低浓度的溶液13 180 45（克）需要 40%高浓度的溶液180 135（克）需要 20%低浓度的溶液答：需要 40%的溶液 45 克，需要 20%的溶液 135 克。解法二：设需要 40%的溶液 x 克，需要 20%的溶液（180-x）克。40%x20%（180-x）180 25%0.4x36-0.2x45 0.2x9 x45需要 40%高浓度的溶液180-45135（克）需要 20%低浓度的溶液答：需要 40%的溶液 45 克，需要 20%的溶液 135 克。通过以上例题，我们可以

46、看出，解题时要善于抓住事物间的联系，进行适当转化，就能发现其中的规律，找到解决问题的巧妙方法。文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5

47、L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H

48、5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4

49、H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A

50、4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9A4H5L9W10文档编码:CM9H2D9W10P2 HF8N2N7F10P5 ZW9