Is Matter around Us Pure Test - 4

Solidified carbon dioxide is called dry ice.

Salt dissolves in water whereas sand remains undissolved and thus can be filtered.

Water gets evaporated from sea water and salt residue is left behind.

Sea water is trapped in shallow lakes called lagoons in order to obtain common salt from it.

A colloid with a solid dispersed phase and liquid dispersing medium is called sol.

An element is a pure substance that cannot be broken down by any physical or chemical means into a simpler substances. Tin (Sn) is an element. Whereas, water (H₂O), hydrogen sulphide (H₂S) and ammonia (NH₄) are compounds.

In a physical change, no new substance is formed. The composition of bits of paper remains unchanged. Hence, tearing of paper is a physical change.

A drop of sample whose components need to be separated is placed on the filter paper.

Water from the reservoir is directed to  sedimentation tank where insoluble solids settle.

Then, water enters loading tank where suspended impurities are sedimented.

Next, water is directed to filtration tank where all the suspended impurities are removed.

Finally, water enters the chlorination tank where water is treated with chlorine to kill any bacteria present in the drinking water.