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Usually the smallest molecules are gaseous or liquid at room temperature and the large
molecules are solids. Perspex and polystyrene are solid polymers, which can be broken down
to smaller molecules by heat. Put pieces of Perspex or polystyrene in a hard glass test-tube.
Connect a delivery tube.From large molecules to small molecules A Perspex or
polystyrene B receiving tube c cold water D a liquid collects. The collecting test-tube must
be cooled thoroughly with cold water, as the fumes are harmful. Gently heat the test-tube
containing the Perspex. The polymer will melt and give off vapours, which are collected in
the receiving tube. Heating must be carefully controlled to enable all the fumes to be
condensed in the receiving tube. A liquid is obtained. This suggests that the polymer has
been broken down by heat to smaller molecules. The liquid does not return to the solid state
unless a catalyst is used. The specific catalysts are not usually available in school
laboratories.
sharon kalunda answered the question on April 12, 2019 at 09:28
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