醋酸钠的过饱和现象.doc

Sodium acetate supersaturated phenomenon首先把醋酸钠放入容器中 加水 加热待溶液澄清后 放入冰箱冷却然后准备一个盒子重点来了：此盒子必须干净 清洁 并且表面光滑 术语就是 不能有晶种Then dump原理的话 和晶种有关加热的情况下 醋酸钠过饱和度非常高 并且不稳定在冰箱中冷却更加剧了不饱和度然后用手触摸的时候， 手部的灰尘颗粒 或者甚至是指纹都回作为晶种 引起醋酸钠瞬间的析出 析出的醋酸钠又作为晶种 成为其过饱和溶液的析出原因 ：一定温度、压力下，当溶液中溶质的浓度已超过该温度、压力下溶质的溶解度，而溶质仍不析出的现象叫过饱和现象，此时的溶液称为过饱和溶液。 每一种晶体都有一定的排列规则，要有结晶中心使做无秩序运动着的溶质集合起来，并且按照该晶体所特有的次序排列起来。不同的物质，实现这种规则排列的难易程度不同，有些晶体要经过相当长的时间才能自行产生结晶中心。而过饱和溶液并非处于平衡状态，受到振动或者加入溶质的晶体，则溶液里过量的溶质就会析出而成为饱和溶液，即转化为稳定状态，这说明过饱和溶液没有饱和溶液稳定，但还有一定的稳定性。因此，这种状态又叫介稳状态。First put the sodium acetate in the container Add hot water. Then wait for solution to clear and cold. key: the container of Solution must be quite clean and has a smooth surface. The term is no seed Then dump Supersaturated [s?t??re?t]?使饱和solution is not in balance, crystal [kr?st(?)l] n. 结晶，晶体by vibration [va?bre??(?)n] n. 振动, excessive [?kses?v;] adj. 过多的amounts of solute溶质 in the solution would precipitate [pr?s?p?te?t]沉淀and become saturated[s?t??re?t]饱和的 solution, which is converted into a stable state,Vibration cause the precipitation .And the precipitation of sodium acetate instant become the seed of supersaturated solution. this suggests that the supersaturated solution not saturated solution is more stable than the supersaturated solution, but there is still a certain stability when it is supersaturated. Therefore, the state is also called the steady state interface.