1. Pure Substances Mr. Skirbst Physical Science Topic 12

2. Pure Substances

3. Made of only one kind of material and has definite properties

4. Pure Substances Elements – simplest pure substance

5. Pure Substances Elements – simplest pure substance Atoms – basic building block of all matter (simplest part of an element)

6. Pure Substances Elements – simplest pure substance Atoms – basic building block of all matter (simplest part of an element) Symbols – element shorthand

7. Pure Substances Compounds – - pure substance made of more than one element (chemically combined) - can be chemically broken down

8. Pure Substances Compounds – - pure substance made of more than one element (chemically combined) - can be chemically broken down Molecule – smallest part of a compound keeping characteristics

9. Chemical Formulas Shorthand for chemical substances (ex. H 2 O, NaCl, CO 2, HCl) Subscript - # of atoms

10. Chemical Equations Shorthand for chemical reaction Ex. Coefficient - # of molecules Yields – arrow indicating direction of reaction

11. Chemical Equations 2 Fe + 3 S  Fe 2 S 3 (reactants) (yields) (products)