vacuum-insulated reaction flask<>approximates<>the condition of a isolated system$$$neither matter nor heat<>can be exchanged<>a isolated system
Although in principle, the HeHg laser can be operated in 'sealed tube' fashion, as a practical matter, maintaining a connection to the vacuum system will be essential.
A sealed, vacuum-insulated reaction flask approximates the condition of a isolated system, in which neither matter nor heat can be exchanged between system and surroundings.
A sealed, vacuum-insulated reaction flask approximates what condition, in which neither matter nor heat can be exchanged between system and surroundings?