Question

note: to answer some of the questions, it may help to reference a periodic table
checkpoint 17
study the lab scenario.
during an experiment, a crackling noise can be heard while a substance is heated.
how does the scenario indicate a chemical reaction is occurring?
the release of energy through noise is a sign of a chemical reaction.
the formation of a precipitate is a sign of a chemical reaction.
a change in odor is a sign of a chemical reaction.
the release of energy through temperature is a sign of a chemical reaction.

Explanation:

A chemical reaction can be indicated by various signs. In this scenario, the crackling noise is a form of energy release (sound energy). The other options like formation of precipitate (solid from solution), change in odor (new smell from new substances), and release of energy through temperature (heat) are also signs of chemical reactions but do not match the "crackling noise" description.

Answer:

The release of energy through noise is a sign of a chemical reaction.