Closed System: - A system in which there is only the exchange of energy between system and surroundings.

Open System: - A system in which there is an exchange of both matter and energy is termed as an Open System.

Reason: -

(i) As the system is covered, there will be no exchange of matter and the system cannot be considered as an open system.

(ii) As mentioned above there will be only the exchange of energy between system and surroundings in a closed system.

(iii) In a closed vessel there will be no exchanged of matter but there will be an exchange of energy which will be taken place through the wall of the copper vessel. So, it can be considered a closed system.

(iv) In closed vessels, there will be exchange of energy, but insulation will restrict the exchange of energy between the system and surroundings.