Question

what is a key indicator that a chemical change has occurred? * a change in shape a change in temperature, color, or a gas forming a change from a liquid to a solid a phase change from solid to liquid

Explanation:

A chemical change is characterized by the formation of new substances. Indicators include a change in temperature (exothermic or endothermic reactions), color change (due to the formation of new compounds with different absorption - reflection properties), or gas formation (a new gaseous product is created). Phase changes and changes in shape are physical changes, not chemical changes.

Answer:

A change in temperature, color, or a gas forming