1. Chp 2. MATTER & MATERIALS

2. 2.1 Chemistry A branch of science that deals with the composition, structure, properties and reactions (transformations) of matter.

3. 2.1 DESCRIPTION OF MATTER Substances that are visible and invisible (anything that has mass and occupies space) Substances that are living and nonliving

4. 2.1 Matter doesn’t include energy, in its various forms (E.g., heat, light, electricity) All transformations of matter involve energy changes. Chemist are interested in the energy changes that occur when matter is transformed.

5. MATTER Can it be physically separated? MIXTURE PURE SUBSTANCE yes no

6. 2.2 Pure Substance (Substance) Matter that cannot be separated into other kinds of matter using physical means. Examples Sugar, ammonia, water, and oxygen. It has a fixed composition and distinct properties.

7. 2.2 Mixtures Matter containing 2 or more substances in which each substance retains its own identity. Separable into individual substances by physical means. Mixtures can exist in any combination of pure substances. Therefore the composition of a mixture is variable.

8. MATTER Can it be physically separated? MIXTUREPURE SUBSTANCE yesno 1.Only one substance present 2.Definite and constant composition 3.Properties are always same under given set of conditions 1.Physical combination of two or more substances 2.Variable composition 3.Properties vary as composition varies 4.Components can be separated by physical means

9. 2.10 PHYSICAL SEPARATION METHODS  Use physical properties and changes to separate mixtures.  Melting point (freezing point)  Boiling point (condensation point)  Water solubility (dissolving)  Density  Techniques include:  Distillation  Filtration  Magnetism  Floatation

10. 2.2 Mixture subclassifications Heterogeneous Homogeneous

11. Homogeneous Mixture (solution) Heterogeneous Mixture MIXTURE Is the composition uniform? noyes These are physical classifications based on observation of the matter MATTER Can it be physically separated? PURE SUBSTANCE yes no

12.  A mixture is a variable combination of 2 or more pure substances. Heterogeneous Homogeneous

13.  Homogeneous (solution)  One visibly distinguishable phase (uniform appearance)  Uniform properties throughout the phase  particles don’t settle  EX: rubbing alcohol

14.  Heterogeneous  Observe two or more visible phases  Each phase has different properties  particles settle  EX:fresh-squeezed lemonade

15. MATTER Can it be physically separated? Can it be chemically decomposed? Compound Element PURE SUBSTANCE no yes Homogeneous Mixture (solution) Heterogeneous Mixture MIXTURE yes Is the composition uniform? noyes 2.2 Pure Substances

16.  Element  composed of identical atoms  Cannot be broken down into simpler substances using chemical methods  EX: copper wire, aluminum foil 2.2 Pure Substances

17.  COMPOUND  composed of 2 or more elements in a fixed ratio  properties differ from those of individual elements  Cannot be separated by physical means  Separated by chemical means  EX: table salt (NaCl)

18. Substances and Mixtures  Examples:  Graphite (all C atoms)  pepper  sugar (sucrose)  paint  gasoline