How do you know a chemical reaction has taken place?

When mixing 2 chemicals together – how do you know if a reaction occurs?  Create a gas  Change color  Releases heat (feels hot) or absorbs heat (feels cold)  Create a precipitate (solid made from 2 clear liquids)

Copy each chemical equation. Balance & Classify each equation.

Copy:  Write the phases of matter  Balance  Classify  Evidence of a chemical reaction MnO2

Copy:  Write the phases of matter  Balance  Classify  Evidence of a chemical reaction

Copy:  Write the phases of matter  Balance  Classify  Evidence of a chemical reaction

Copy:  Write the phases of matter  Balance  Classify  Evidence of a chemical reaction

Copy:  Write the phases of matter  Balance  Classify  Evidence of a chemical reaction

Copy:  Write the phases of matter  Balance  Classify  Evidence of a chemical reaction

Copy:  Write the phases of matter  Balance  Evidence of a chemical reaction

Copy:  Write the phases of matter  Balance  Classify  Evidence of a chemical reaction

Copy:  Predict the products  Write the phases of matter  Balance  Classify  Evidence of a chemical reaction