Question

note: to answer some of the questions, it may help to reference a periodic table
checkpoint 17
listen
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 often involves energy changes. Noise (sound energy) can be a form of energy release during a chemical reaction. Precipitate formation (solid from solution mixing), odor change (new substances with different smells), and temperature - related energy release (like heat) are also signs. But the scenario specifically mentions a "crackling noise", which directly relates to energy release as noise.

Answer:

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