Which of the following would be evidence that a chemical reaction has occurred? (Select all that apply.) *

a change in shape
a precipitate is formed
an unexpected change in color
the formation of gas bubbles
smoke begins to form
clear liquids remain clear
the odor changes
the substance becomes very cold

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

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water