Question

Fill in the blanks:

The mixture of iron filings and sesulphur powder can be separated by using………..

Filtration is a process by which insoluble solids can be removed from a liquid by using a…………..

Silica gel placed in water vapours results in ………….. whereas calcium chloride placed in water vapours results in…………..

Colloidal dispersion of a liquid in a gas is called…………….

Scattering of light by colloidal particles is called………………



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Answer 1

Answer:

1] Demonstrate that iron can be separated from the mixture by physical means. Do this by wrapping the end of a small bar magnet in a paper tissue or cling film, and dipping it into a teaspoon-sized heap of the mixture on a watch glass. The iron will be attracted, but the sulfur remains on the watch glass.

2] Filtration is a method for separating an insoluble solid from a liquid. When a mixture of sand and water is filtered: the sand stays behind in the filter paper (it becomes the residue ) the water passes through the filter paper (it becomes the filtrate )

3] Anhydrous CaCl2 will absorb the water vapours while silica gel will adbsorb the vapours. As for the difference between absorption and adsorption, (apart from the 'b' and 'd' !) the former is a bulk phenomenon, while the latter a surface phenomenon.

4] (Also called colloidal dispersion, colloidal suspension.) ... A system of liquid or solid particles colloidally dispersed in a gas is called an aerosol. A system of solid substance or water-insoluble liquid colloidally dispersed in liquid water is called a hydrosol.

5] The Tyndall effect is light scattering by particles in a colloid or in a very fine suspension. ... It is named after the 19th-century physicist John Tyndall.