The concentration of a salt solution in terms of mass by mass percentage is $20 \%$ and the mass of the solution is $550 \text{ g}$. Determine the mass of solute present in the solution. (in $\text{ g}$)

The 'sea-water' can be classified as a homogeneous as well as heterogeneous mixture. Comment.

How are colloids different from suspensions? Identify the colloids from the following: Soda water,milk,sponge,clouds,mixture of alcohol and water,jelly.

What are the two components of a solution?

Name the process associated with the following:
$(a)$ Dry ice is kept at room temperature and at one atmospheric pressure.
$(b)$ $A$ drop of ink placed on the surface of water contained in a glass spreads throughout the water.
$(c)$ $A$ potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring.
$(d)$ An acetone bottle is left open and the bottle becomes empty.
$(e)$ Milk is churned to separate cream from it.
$(f)$ Settling of sand when a mixture of sand and water is left undisturbed for some time.
$(g)$ $A$ fine beam of light entering through a small hole in a dark room illuminates the particles in its path.

Crystallisation is a better technique than simple evaporation. Give one reason to justify the statement.