1. Properties of Matter

2. Matter – Anything that has mass and takes up space. Chemistry – Study of matter All matter has physical and chemical properties: Physical Property – Observed without changing the substance’s composition. -Example – The freezing of water Chemical Property – Observed by changing the substance’s composition -Example – Burning paper into ash and carbon dioxide.

3. Pure Substance – Matter that has the same composition throughout. Type of Pure Substance DefinitionSmallest Unit of Matter Elements Matter that cannot be broken down into simpler substances (Example: Oxygen) Atom Compounds Matter made from two or more substances in a fixed ratio. (Example (Water – H 2 O) Cannot be separated by a physical change Molecule

4. Impure Substances Mixtures do not have consistent chemical compositions throughout. Components are not chemically combined. Can be separated by a physical change. Type of MixtureDefinitionExample HomogeneousMixture where parts are hard to distinguish Solution (Ex: Salt water) HeterogeneousMixture where parts are easy to distinguish Suspension (Oil and water)

5. Physical Properties Viscosity = A fluid’s resistance to flow Conductivity = ability to allow heat flow Malleability = ability to hammer without shattering Hardness = ability to scratch other objects Temperature – average energy of atoms/molecules of a substance. Melting Point = temperature at which a substance goes from solid to liquid Boiling Point = temperature at which a substance goes from liquid to gas Density = ratio of mass to volume

6. More on Density A measure of how many atoms are in a enclosed area. The closer together the atoms, the more dense the object is. Calculation to determine density is D= M/V

7. Density Problems An object has the mass 0f 32 g and a volume of 72 cm 3. What is the Density of this object? Will this object sink or float? An object has the mass of 162 g and has a volume of 46 cm 3. What is its density? Will this object sink or float?

8. Chemical Properties Chemical Properties = properties that can be observed only when a substance is changing into a different substance Flammability = ability to burn in the presence of oxygen Reactivity = how readily a substance combines with other substances

9. Physical Changes Occurs when some of the properties of the material change, but the chemical composition remains the same.

10. Chemical Changes Recognizing Chemical Changes Change in Color Gas Production Precipitate Formation -any solid that forms and separates from a liquid

11. Chemical or Physical Change? Physical Chemical Physical