[{"from": "human", "value": "Describe this molecule. [C][=C][C][=O]"}, {"from": "gpt", "value": "The molecule appears as a colorless to yellow volatile liquid with a disagreeable choking odor. Flash point below 0 \u00b0F. Initially irritating to the eyes and mucous membranes. Very toxic by inhalation. Less dense than water (7.0 lb / gal). Vapors heavier than air. Used to make other chemicals, plastics, and as a herbicide.   Rate of onset: Immediate  Persistence: Minutes to hour  Odor threshold: 1 ppm  Source/use/other hazard: Herbicide; tox and corrosive fumes."}]