Signs of a Chemical Reactions

Front

What is a sign that a chemical reaction has occurred?

Back

Evidence such as color change, gas production, temperature change, or formation of a precipitate.

Front

What is the most indicative observation of a chemical reaction?

Back

The formation of a new substance, such as a color change or gas release.

Front

What does evidence of a chemical reaction indicate?

Back

It indicates that a new substance has formed.

Front

What is an example of evidence of a chemical reaction?

Back

Burning sugar gives off an odor and changes color from white to brown and then black.

Front

What indicates that a new substance was formed when mixing two clear liquids?

Back

The formation of a yellow solid that settles to the bottom of the beaker.

Front

What are the common signs of a chemical reaction?

Back

Color change, gas production, temperature change, and formation of a precipitate.

Front

What is a precipitate?

Back

A solid that forms and settles out of a liquid mixture during a chemical reaction.

Front

How can temperature change indicate a chemical reaction?

Back

If the reaction releases heat, it is exothermic; if it absorbs heat, it is endothermic.

Front

What role does odor play in identifying a chemical reaction?

Back

The production of a gas with a distinct odor can indicate a chemical change.

Front

What is the difference between a physical change and a chemical change?

Back

A physical change does not alter the substance's chemical composition, while a chemical change does.