您将如何区分胶体和溶液?
胶体是一种混合物,其中一种材料悬浮在另一种物质中并含有分散的不溶性颗粒。整个混合物称为胶体溶液。胶体具有分散相(悬浮颗粒)和连续相,与溶液不同,溶液仅具有溶质和溶剂(悬浮介质)的一个相。要归类为胶体,混合物必须不能沉降或沉降非常缓慢。
胶体类型
分散物质的相和它被分散的相是表征胶体的两种典型方法。溶胶、乳液、泡沫和气溶胶是胶体的例子。
- 固体颗粒在液体中的胶态分散体称为溶胶。
- 两种或多种液体的混合物称为乳液。
- 当大量气体颗粒被困在液体或固体中时,就会产生泡沫。
- 气溶胶由悬浮在气体中的小液体或固体颗粒组成。
当分散介质为水时,胶体体系称为水胶体。根据可用的水量,分散相中的颗粒可能会经历几个阶段。果冻粉与水混合时会产生水胶体。医用敷料是水胶体的一种流行应用。 Dispersed Material Dispersed in Gas Dispersed in Liquid Dispersed in Gas Gas (Bubbles) Not possible Liquid (Droplets) Mist, Clouds Solid (Grains) Dust, Industrial SmokeFoams: Whipped Cream Solid foams: Plaster Emulsions: Milk, Blood Butter Sols and Gels: Muddy water, Starch Solution Solid Sol: Pearl
胶体的物理性质:
- 异质性:胶体溶液本质上是异质的,具有两个不同的相:分散和分散介质。
- 解决方案的性质:解决方案非常稳定。它们一直在运动,从不停留在容器的底部。
- 过滤性:胶体颗粒轻松流过标准过滤片。
胶体的依数性质:
- 由于连接分子的产生,观测到的依数性质值,例如相对降低的蒸汽压、升高的沸点、降低的冰点和渗透压,比预期的要小。
- 特定溶液中的粒子数量将非常少。
胶体的机械性能:
- 扩散:溶胶粒子从高浓度区域向低浓度区域扩散。然而,由于它们的尺寸较大,它们确实以较慢的速度扩散。
- 沉降:在重力作用下,胶体颗粒以非常缓慢的速度沉降。使用这种现象确定大分子的分子量。
胶体和溶液之间的相似之处:真正的溶液是液相组合,其中溶质和溶剂完全结合。胶体溶液是溶质(小颗粒或胶体)均匀分布在整个溶剂(液相)中的混合物。
廷德尔效应
使用 Tindall 效应,我们可以区分胶体和真实溶液之间的区别。胶体是一种将穿过它的光线散射并使其路径可见的溶液。一个真正的解决方案是不散射穿过它的光束并且不使其路径可见。
The Tyndall effect is a phenomena in which light beams are scattered by the particles in a colloid. All colloidal fluids and certain very fine suspensions exhibit this effect. As a result, it may be used to identify whether or not a solution is a colloid. The density of colloidal particles, as well as the frequency of incident light, determine the intensity of scattered light.
溶液中的胶体颗粒会阻止光束在穿过胶体时完全穿过它。当光与胶体粒子碰撞时,它会发生散射(它偏离了它的正常轨迹,它是一条直线)。由于这种色散,光束的路径是可见的。与红光相比,蓝光的散射量更高。这是因为蓝光的波长比红光短。这就是为什么摩托车排放的烟雾有时会呈现蓝色的原因。
区分胶体和溶液
- 真溶液是均质的,而胶体溶液本质上是异质的。
- 真溶液溶剂粒径小于 1 nm,但胶体溶液溶剂粒径范围为 1 nm 至 1000 nm。
- 即使在超显微镜下,也看不到真溶液颗粒,但可以看到胶体溶液颗粒。
- Tyndall 效应不会出现在真实溶液中,而是出现在胶体溶液中。
乳液:乳液是一种胶体,包括黄油和蛋黄酱。液体在液体或固体中的胶态分散体称为乳液。稳定的乳液需要乳化剂。油和醋用于制作蛋黄酱。因为油是非极性的而醋是极性水溶液,所以两者不会混合并快速分离成层。另一方面,蛋黄的加入可以稳定混合物并防止其分离。极性醋和非极性油都可以与蛋黄相互作用。乳化剂是鸡蛋的蛋黄。
示例问题
问题一:胶体有哪些种类?
回答:
The phase of the dispersed substance and the phase in which it is disseminated are two typical methods of characterizing colloids. Sol, emulsion, foam, and aerosol are examples of colloids.
- A colloidal dispersion of solid particles in a liquid is known as sol.
- A blend of two or more liquids is known as an emulsion.
- When a large number of gas particles are trapped in a liquid or solid, foam is created.
- Aerosols are made up of small liquid or solid particles suspended in a gas.
问题 2:什么类型的混合物是烟雾弹?
回答:
Assume you’re on a yacht sailing. The engine fails unexpectedly, leaving you adrift in the midst of the ocean. You call the Coast Guard on your radio, but your GPS isn’t working, so you can’t tell them a precise location. You have a smoke flare, which you use to clear the area. The dense colored smoke alerts the Coast Guard to your location, allowing them to rescue you. When you use the flare, you’re using a colloid, which is a form of mixture.
问题 3:以下哪项会显示廷德尔效应,为什么?
盐溶液、牛奶、硫酸铜溶液和淀粉溶液。
回答:
The Tyndall effect can be seen in milk and starch solutions.
The Tyndall effect describes how the particles in a colloid scatter the light rays that are focused at them. This effect can be seen in all colloidal solutions including certain very tiny suspensions. As a result, it can be used to determine if a given solution is a colloid. The intensity of scattered light is determined by the density of colloidal particles as well as the incident light frequency.
问题 4:举一些廷德尔效应的例子。
回答:
Milk is a colloid that consists of fat and protein globules. When a beam of light is aimed towards a glass of milk, the light is dispersed. The Tyndall effect is perfectly described in this way. When a torch is turned on in a foggy environment, the direction of the light becomes apparent. The dispersion of light in this scenario is due to the water droplets in the fog.
问题 5:什么是廷德尔效应?
回答:
The Tindall effect is a phenomena in which light beams are scattered by the particles in a colloid. All colloidal fluids and certain very fine suspensions exhibit this effect. As a result, it may be used to identify whether or not a solution is a colloid. The density of colloidal particles, as well as the frequency of incident light, determine the intensity of scattered light.