You will be given a definition of a task first, then some input of the task.
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

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.
Output:
A sealed, vacuum-insulated reaction flask approximates what condition, in which neither matter nor heat can be exchanged between system and surroundings?