CONCENTRATION PROBLEM
浓度问题,混合稀释秒解。
随机生成盐水浓度混合与稀释问题,求最终浓度,附溶质守恒公式解法步骤,典型小学奥数题。
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解题动画 · 溶质守恒
这是什么?
浓度问题的核心是「溶质守恒」:混合或稀释前后,溶质(盐)的总量不变。浓度 = 溶质 ÷ 溶液 × 100%。两液混合:浓度 =(X×A% + Y×B%)÷(X+Y);加水稀释:浓度 = X×A% ÷(X+Y水)。抓住「盐不变」这一关键,所有浓度题迎刃而解。下方随机出题自测。
示例与注意事项Example & notes
一个例子A worked example
20% 糖水 200 克再加水 50 克:溶质仍是 40 克、溶液变成 250 克,浓度降到 16%。200 g of 20% syrup plus 50 g of water keeps 40 g of solute in 250 g of solution — a 16% concentration.
注意事项Things to watch
- 稀释与混合题的抓手永远是「溶质守恒」,先算溶质再算浓度。Dilution and mixing always reduce to conserving solute — find the solute first.
- 百分比指质量分数而非体积分数,配液时要看清题目单位。Percentages here are mass fractions, not volume — check the units in the question.
- 两液混合后的浓度必在两者之间,可用来快速检错。A mixture always lands between the two concentrations — a quick sanity check.
相关问答More Q&A
能反求加多少水吗?Can it solve for the water needed?
可以,输入目标浓度即可反解需要加入的水量或溶质。Yes — enter the target concentration and it works out the water or solute required.
有动画演示吗?Is there an animation?
有,混液动画会展示颜色随浓度收敛的过程。Yes — the mixing animation shows the colour converging as concentration settles.