5 Signs of a Chemical Reaction

5 Signs of a Chemical Reaction
Color change
Increase or decrease in temperature
Gas production (not boiling)
Precipitation: 2 liquids react to make a solid
Change in properties (density, smell, taste,
texture, melting points, boiling points,
hardness, etc.)
Did a chemical reaction take place?
Write a paragraph on the other side of the paper
that answers the above question. Be sure to:
1. Write a topic sentence.
2. Have at least 4 concrete detailed sentences.
3. Those 4 sentences should clearly state which
signs of a chemical reaction were present and
describe what happened.
4. Write a closing sentence.
You are to quietly write this by yourself without
Yes a chemical reaction did take place!
We know because:
1. The properties changed: It got a lot larger.
2. The temperature changed. The temperature
rose, the cup got warmer.
3. A gas was produced. You could seem the
small bubbles forming everywhere.
4. A precipitate formed. 2 liquids changed to a
A chemical reaction took place when the 2 chemicals were mixed
because 4 signs of a chemical reaction were observed.
The properties of the chemicals changed. They started out very
small and grew to something very large. The reaction was
exothermic. Heat was released and the cup got warmer. Gas
was produced during the chemical reaction. Little bubbles
formed throughout the mixture. A precipitate formed. The
starting chemicals were liquids, the product was a solid.
Properties changing, heat being released, gas production, and a
precipitate prove that a chemical reaction did take place.

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