Solutions And Crystallisations

Question 1

Solutes, solvents and solutions

Answer 1

In a solution, the substance which dissolves is called the solute.
The substance in which the solute dissolves is known as the solvent.
A solution is formed when a solute dissolves in a solvent.

Question 2

Concentrated and dilute solutions

Answer 2

Have you ever tried tasting drinks like ‘MiWadi’’ without adding water first? They taste very sweet. These types of drinks are concentrated solutions. This means there is a lot
of solute dissolved in the solvent. By adding water to the concentrated solution of ‘‘MiWadi’’ you are making the solution more dilute and nicer to taste.
If you add too much water the drink may taste too weak. What could you do to make it more concentrated again?

Question 3

Soluble and insoluble

Answer 3

When a solute dissolves it does not disappear. It is still present and fills the gaps between the solvent particles, so there is no change in volume.
Note, however, that the mass of the solution is equal to the mass of the solute and the solvent.
A solid is said to be insoluble if it does not dissolve in a solvent. The solid may settle to the bottom of the liquid, or may end up scattered throughout the liquid, forming a suspension.

Question 4

Crystallisation

Answer 4

The formation of crystals by cooling a saturated solution

Question 5

Solutions

Answer 5

When we think about solutions, we usually think of them as a solid dissolved in a liquid, e.g. seawater. However, solutions can be very different to this. For example:
Oxygen dissolves in water to form a solution which allows fish to breathe.
Marshmallows are solutions where air is dissolved in a sugary paste.