Chemistry Test - 66

A device used for the measurement of radioactivity is G.M.counter.

A small organic molecule (sugars or amino acids), several of which may be bonded together to form a chain called a polymer.

Because of its being pollution free and combustion efficient, Hydrogen gas is called fuel of future. Because of its origin in marshy places, Methane is called as 'Marsh Gas'.

Terylene and nylon are synthetic fibres produced by a process of polymerisation. Terylene is a polyester and nylon, a poyamide.

Silk is purely a natural product obtained from silk worms.

Rayon is a man-made material which consists of purified cellulose in the form of long fibres. Cellulose occurs in the cell wall of plants. Rayon fibre is chemically identical to cotton but has a shine like silk. Since it is basically derived from a natural source (cellulose) it is called a regenerated fibre.

The law of constant proportions was enunciated by Proust.

ΔT_f = k_f. m

for ethylene glycol in aq. solution

ΔT_f = k_f w / mol.wt × 1000 / wt. of solvent

6 = (1.86 x w x 1000) / (62 x 4000)

=> w = 800 g

So, the weight of solute should be more than 800 g.

Vapour of carbon tetra chloride (ccl₄) is non-inflammable and is heavier than air. Hence it is used as a fire extinguisher under the trade name of pyrene.

The maximum number of hydrogen bonds in a water molecule is 4.

Cutting and Peeling of onion brings Tears to the eyes because of presence of Sulphur in the cell

Species containing same number of electrons are called Isoelectronic.