a precipitate is formed: is a chemical reaction because a different solid substance is formed
unexpected color change: is a chemical reaction indicating that a reaction is occurring
the formation of gas bubbles: is an indication of a chemical reaction taking place
smoke begins forming: when we burn wood it releases energy in the form of heat and creates new substances such as smoke and ash
the odor changes: when two or more compounds or elements are mixed and a scent or odor is present a chemical reaction has taken place for example when an egg begins to smell
hope this helps, can i get brainliest
