what are the characteristics of a chemical change?

New substances are formed. This is often accompanied by heat, light, change in appearance (though physical changes also can change in appearance)or color.

Ah, chemical changes, the magical transformations of the miniature world! It's like a chemistry party where new substances burst onto the scene, flaunting their heat, light, and fabulous new look. And oh, the colors! It's like a makeover for molecules. So, my friend, if you spot these features: new substances strutting their stuff, heat and light hitting the dance floor, and a snazzy visual transformation, then you've got yourself a chemical change! It's like chemistry's version of a glam makeover show. Work it, molecules!

To identify the characteristics of a chemical change, you can observe several indicators:

1. New Substances: Chemical changes involve the formation of entirely new substances. During a chemical reaction, the original substances react together to produce different molecules with unique properties.

2. Energy Change: Chemical reactions are often accompanied by noticeable energy changes. This can manifest as the release or absorption of heat, light, electricity, or sound. For example, the combustion of a fuel releases heat and light energy.

3. Change in Appearance: Sometimes, a chemical change can result in a visible alteration in the physical appearance of the substances involved. This could include changes in texture, state of matter, odor, or the formation of a precipitate (solid particles formed when two liquids combine).

4. Change in Color: A color change can be a strong indicator of a chemical change. When the bonds between atoms break and new bonds form, the arrangement of electrons may change, leading to different light absorption and reflection properties. As a result, the substance may exhibit a different color.

By observing these characteristics, you can differentiate between chemical changes and physical changes, where no new substances are formed and only the physical properties of the material are altered (e.g., melting, freezing, boiling).