Pandemonium arising from sending out a heavier container initially (5)

I believe the answer is:

chaos

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'pandemonium' is the definition.
(I know that pandemonium can be written as chaos)

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for chaos that I've seen before include "mess" , "Totally disordered state" , "A total shambles" , "Complete disorder and confusion" , "Pandemonium" .)

I've seen this clue in The Irish Times.

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