Question

Explain why thermo-flask can be designated as an ideal isolated system though the liquid kept in it may change its temperature after several hours: ​

Answer 1

Answer:

A flask or a thermos keeps hot liquids hot and cold liquids cold. The basic principle behind the working of a flask is to insulate the substance from the outside air so that no heat transfer takes place. When there is no heat transfer, the temperature of the substance remains the same.

Explanation:

Answer 2

A thermos flask has inner wall of glass which has very low conductivity for heat. Then outer side has an air chamber which is a worse conductor of heat. It is followed by a layer of heat resistant material like thermocol which further does not let energy tranfer to the surroundings.

There is no perfect adiabatic system, some loss of heat is obvious to happen. Still it impressively reduces the rate of cooling.

All the very best..