2. Properties of Matter Chapter 2

4. Pure Substances ELEMENTS Cannot be broken down into simpler substances. Can be found as solids, liquids, or gases Represented by symbols COMPOUNDS 2 more elements chemically joined together Can be broken down through chemical means Represented by a formula

5. Mixtures Homogenous Appear the same throughout. Well-mixed Examples: Heterogeneous Can see different parts Not very well mixed Examples:

6. The best mixed mixture. One substance is dissolved in another. Cannot be separated by filtering Particles are too small to be seen

7. A heterogeneous mixture that will separate over time The particles in a suspension are larger than the particles dissolved in a solution Cloudy appearance Examples: muddy water, oil & vinegar salad dressing

8. Intermediate sized particles. Smaller than suspension but larger than solution. Particles are permanently suspended Will scatter light

9. Physical Properties A characteristic of matter that can be directly observed without changing the identity of the substance

10. Viscosity The resistance of flow in a liquid How “thick” or “thin” a liquid is Examples of substance that have high viscosity:

11. Conductivity The ability to conduct heat or an electric current High conductivity: metals Low conductivity: wood, rubber

12. Malleability vs ductility MALLEABLE Ability to be hammered into a thin sheet. Example: DUCTILE Ability to be drawn into a thin wire. Example:

13. Melting and Boiling Points Very useful in determining unknown substances.

14. Density The amount of mass per unit volume D = M/V

15. Separating Mixtures Filtration = using a strainer or filter to separate on the basis of size of the particles.

16. Distillation A means of separating substances in a mixture or solution by differences in their boiling points.

17. Chemical properties Flammability : a materials ability to burn in the presence of oxygen Reactivity : how easily a chemical reacts with other substances. Health : degree of danger to humans

18. Signs of a chemical reaction 1.Change in color 2.Production of a gas 3.Formation of a precipitate

19. Assignment: Pages 63-64 1-10,12,15,26,27 Page 65 1-6