1. Chp 3 Matter

2. Substance (pure substance) – uniform and unchanging composition Examples: Counterexamples:

3. I. Properties Physical: can be observed w/o changing composition of matter – Intensive – properties of material itself – Extensive – properties of your sample only

4. Classify Identify each as an intensive or extensive property for a sample of gold. – Yellow___ – Mass = 45g ____ – Density = 19.3g/cm 3 ____ – Lusterous ____ – 25 o C ____ – Melting point = 1100 o C ____ – 14cm long ____ – Malleable ____ – Odorless ____ – Solid at room temp ____

5. Chemical - describes how a type of matter interacts with another type of matter. – Examples Iron rusting Silver tarnishing Wood burning Gold does not oxidize Alcohol is flammable Milk spoils Vinegar reacts with baking soda to for CO 2 gas

6. II. Changes Physical changes – a change that a sample undergoes that does not change the composition Chemical – a new substance is formed – Evidence of chemical change Energy exchange Unexplained color change Gas given off Formation of a precipitate When original conditions don’t bring back original substance

7. Classify as phys or chem change Rotting____ Burning ___ Melting ___ Dissolving ____ Digesting____ Cooking____ Crushing___ Fermenting___

8. In all phys and chem changes, mass reactants = mass products. (Law of Conservation of Mass)

9. III. Classification of Matter A. Mixtures – 2 or more substances mixed in no fixed ratio w/ each sub retaining its own properties – Heterogeneous – different components in mixture can be observed. Composition is not uniform. – Examples: – Homogeneous – components can’t be observed; Composition is uniform. Examples:

10. Separating Mixtures Filtration Crystallization Chromatography Distillation

11. B. Elements – One type of atom – Can’t be separated by chemical or physical means – 88 naturally occurring and common – Have a symbol on the periodic chart

12. C. Compounds – 2 or more elements combined in a fixed ratio – Chemical formula – Properties unlike those of elements it contains – 10,000,000 known with 100,000 new discovered every year – Can be broken down through chem change.

13. Law of Definite Proportions All samples of a compound always have the same % composition. % by mass=(mass element/mass compound)x100 See p. 76 # 20-23

14. Law of Multiple Proportions The same elements can form different compounds with different % compositions. Ratio of ratios is a whole #. Consider A and B

15. Compo und %H%OMass O in 100g per 100g H A11.188.9 B5.8894.1

16. If A is H 2 O, what is B?