1. Chapter 3 Matter Properties and Changes

2. Atom: The smallest particle of an element that retains all the properties of that element –Comprised of protons, neutrons and electrons Element: A pure substance that can’t be broken down by physical or chemical means. –An atom of any element always has the same number of protons.

3. Properties and Changes Substance: Matter that has a uniform unchanging composition –Also known as a pure substance –Ex: water, only composed of two different substances, and can not be separated by physical means. Mixture:Two or more substances combined having variable composition –Ex: salt water, contains two substances, and can be separated by physical means.

4. Types of Substances Compounds –Can be separated by chemical means –Composed of two or more different elements in distinct whole number ratios –Ex: Water, H2O –Ex: Salt, NaCl Elements –Elements can not be separated by chemical means –Ex: Gold, Au –Carbon, C

5. Types of Mixtures Homogeneous –A mixture with no physically distinct parts in the solution. –Ex: Salt water –Ex: air Heterogeneous –A mixture with distinct physical boundaries. –Ex: granite –Ex: orange juice

6. Changes Physical Change: Change that does not alter the chemical composition of the substance. –Ex: Melting ice Chemical Change: One or more substances are changed into other substances –Ex: chemical reaction

7. Physical Properties Properties that do not involve or describe a substance changing into another substance Or, a characteristic that can be observed or measured without changing the sample’s composition. Ex: Melting Point, Boiling Point, Hardness, and Luster

8. Physical Properties Extensive Properties: Depends on the mass of a substance –Ex: Mass, Length, Volume Intensive Properties: Does not depend on the amount of the substance present –Ex: Density, Solubility

9. Chemical Properties The ability of a substance to combine with or change into one or more other substances. –Ex: Iron reacts readily with the oxygen in the air to form iron oxide (rust).