用合适的溶剂分离

我们接触到的许多物质都混合在一起。在这些组合中将两种或多种化学品组合在一起。在其他情况下，这种混合可能无法同时用于家庭和企业。出于我们的目的，我们可能只需要一个（或两个）不同的组合元素。为了使不同的组合在我们的日常生活中可用，我们必须首先将它们分成各自的部分。

Separation of Mixture of two Solids

All the mixtures containing two solid substance can be separated by one of the following methods:

1. By using a suitable solvent
2. By sublimation
3. By using a magnet
4. Gravity Separation
5. Mechanical Separation

使用合适的溶剂进行分离

In some situations, one component of a combination is soluble in a liquid solvent while the other is not. This variation in solubilities can be utilised to separate the elements of a combination. 

例如，糖溶于水，但沙子不溶于水，因此可以使用水作为溶剂分离糖和沙子的混合物。

实验分离沙子和盐的混合物

• 所需仪器：水、盐、沙子、烧杯、过滤漏斗、滤纸、锥形瓶
• 实验：将混合物放入烧杯中并加入水。然后搅拌以将盐溶解在水中。不溶于水的沙子不会溶解。将含有沙子的盐溶液倒在漏斗中的滤纸上。沙子以残留物的形式留在滤纸上，而盐溶液作为滤液在保持在漏斗下方的烧杯中获得。通过使用类似的过程，可以分离沙子和硫的混合物，但这里将使用二硫化碳作为溶液。

通过合适的溶剂进行分离的例子

1. 分离硫、盐和沙子的混合物：将混合物溶解在二硫化碳中。硫会溶解在其中。现在，我们必须过滤混合物。硫将进入滤液，而沙子和盐将留在滤液中。打开滤液后，我们必须蒸发硫溶液。二硫化碳会蒸发。硫晶体将被留下。然后，溶解水中的残留物并保持容器不受干扰。沙子会沉淀在底部。进行沉淀后，沙子会留在容器中。现在我们可以蒸发溶液并留下盐
2. 分离糖和盐的混合物：与盐不同，糖可溶于酒精和液体石蜡，因此我们可以使用乙醇将其分离。因此，我们必须在糖和盐的混合物中加入乙醇，并使用过滤器将盐从混合物中分离出来。然后，我们可以蒸发乙醇 - 糖混合物以自行获得糖。

合适溶剂的分离应用

1. 合适的溶剂用于去除碳氢化合物。
2. 它还用于去除污染物，例如切削液、油脂、油、蜡和底漆。
3. 这种方法用于soap、制药和石油工业。

示例问题

问题1：怎么回事？

回答：

Matter is anything which occupies space and has mass. When someone says that Matter around us is pure, it means that it consists of a single type of particle. In real world, most of the matter around us is a mixture of two or more pure components instead of pure substance. e.g. Milk, sea water etc.

问题 2：定义混合物。

回答：

Mixture is a combination of various types of matters. For example- Salt and water solution, iron nails in sand etc. It is of two- types- heterogeneous and homogeneous mixtures. 

问题3：有哪些不同类型的混合物？

回答：

Mixtures can be classified into two types- homogeneous mixture and heterogeneous mixture. The former is a mixture which possess same properties and combination throughout their masses. while the latter possess different properties and compositions in various parts.

问题 4：定义离心。

回答：

It is used to separate tiny solid particles that pass through a filter paper which is carried out with the process of centrifugation which in turn, is based on the shape and size of particles, viscosity of the medium and speed of rotation. On rotating the rotor, due to centrifugal force the denser insoluble particles separate from liquid and ends up at the bottom of the tube and the liquid gets collected at the top.

问题 5：定义溶质和溶剂。

回答：

Solute is the substance that dissolves in a solvent to produce a homogeneous mixture. Solvent is the substance in which a solute dissolves to produce a homogeneous mixture. Solute and solvent both can be a gas, liquid or solid. For example, in a salt and water solution, salt is solute and water is solvent.

问题 6：解释使用合适的溶剂分离两种固体的混合物。

回答：

Here, a mixture of two solids can be separated from each other by using a solvent which will make one of the substance soluble in the solvent, thus separating the two substances. e.g. A mixture of sugar and sand can be separated by using water as a solvent as sugar is soluble in water and sand is insoluble in water. This difference in the solubility of sugar and sand in water is used to separate them.

问题7：通过做一个类似于分离沙盐的实验，我们可以分离盐和糖溶液吗？

回答：

No, the solution can not be separated as both salt and sugar are soluble in water, thus making their separation impossible by using a filter paper.