Use of more than one method of separation – Example
Suppose we have powdered sugar mixed in the sand in a container and we have to separate them from one another.
This mixture cannot be physically separated easily. So we need to take the help of some agent that would take away one component from the mixture. In this case, we can add water since sugar dissolves in water.
But we need to only add water which would be enough to dissolve the sugar. This level of water required to just dissolve the entire sugar is called the saturation level. The saturation level is the limit to which a solute can be added to a solvent.
After the water is added to the saturation level, the sugar will dissolve in the water thus forming sugar solution. If this mixture is allowed to sit still for a while, the heavier sand particles will settle at the bottom of the container while the sugar solution will form the upper layer. This is Sedimentation.
Post sedimentation, the sugar solution is very carefully collected in another container. This is
Decantation.
Thus sugar is separated from the sand. But since the water was added externally, the sugar and the water should be separated.
Evaporation can be used to separate sugar from water.
Evaporation, which is converting liquid water into vapour form, will alone not help in this separation because water will be lost when converted to steam. So Condensation, which is the opposite of evaporation should be used simultaneously with the process of evaporation.
The solution of sugar water can be boiled for a long time, and at the same time, an ice-cold lid or a plate can be held over the boiling water. The vapours will touch the colder lid and get condensed. The tilting of the lid will help to collect the condensed vapours, which is water, in
another container. The evaporation will make sure all the water is evaporated leaving behind only sugar in the container.
So now there is sand in the first container, sugar in the second container and water in the third. Thus, sugar, sand, and water are separated.
In this way, multiple methods can be employed for efficiently separating various components of a mixture.