Changes in Matter

Alter a substance without changing the composition Physical Chemical Alter a substance without changing the composition Process in which a substance(s) is changed into one or more new substances; also known as a chemical reaction

Use of symbols to represent a chemical reaction Chemical Equation Use of symbols to represent a chemical reaction CH4 + O2 → CO2 + H2O

“to produce” or “yield” 2 H2 (g) + O2 (g) 2 H2O (l) coefficient Product(s) Reactants “Reacts with” “to produce” or “yield” State of matter

Reactants Products Starting substances Substances formed Found to the left of the arrow in a chemical equation Substances formed Found to the right of the arrow in a chemical equation

Law of Conservation of Mass Mass is neither created nor destroyed during a chemical reaction Massreactants = Massproducts

Chemical Reaction Signs Bubbling (gas production) Color change Precipitate forms (solid formation) Energy change (temperature change) The only way to know for sure is to check the composition before and after the reaction!!!