October 19, 2009 Update your planner. Hand in Combinations of Atoms. Open your book to page 44. Set up your Cornell Notes. Today’s Theme: How can we classify matter?

PROPERTIES OF MATTER Describing Matter

Physical Properties A property of matter that can be observed or measured without changing the identity of the matter.

Physical Properties Physical properties identify matter. Examples include but are not limited to: Density States of Matter (Solid, Liquid, Gas, Plasma) Solubility Freezing point Boiling point Melting point Color Smell Thermal Conductivity Attraction or repulsion to magnets Malleability Ductility Opacity Viscosity

Identifying Substances 2.1

Physical Properties Density is a measure of how much mass is contained in a given unit volume. A measure of how tightly that ‘stuff’ is packed together A ratio of mass to volume Density equals mass divided by volume. Density = mass ÷ volume or

Malleability - The ability to be pounded into thin sheets. Example: Aluminum can be rolled or pounded into sheets to make foil. Ductility - The ability to be drawn or pulled into a wire Example: Copper in wiring – soldering wires or joints Physical Property

Thermal Conductivity - The ability to transfer thermal energy from one area to another. Examples: Plastic foam is a poor conductor, so a hot drink won’t burn your hand. The inside of the toaster (hot coils) are good at transferring heat.

Physical Property Solubility - The ability to dissolve in another substance. Example: Sugar or salt dissolve easily in water but sand dissolves slowly Three ways to increase solubility Heat or make warmer Grind or smash Stir or mix

5 States of Matter Bose-Einstein Condensate Solid Liquid Gas Plasma

Physical Property State of Matter - The physical form in which a substance exists: Bose Einstein Condensate - super-unexcited and super-cold atoms. Solid – matter has a definite shape and volume Liquid – matter takes the shape of its container and has a definite volume Gas – matter changes in both shape and volume Plasma – positively charged atoms (ions) and free electrons.

Bose-Einstein Condensate This state of matter was the only one created while you were alive. In 1995, two scientists, Cornell and Weiman, finally created this new state of matter. Two other scientists, Satyendra Bose and Albert Einstein, had predicted it in the They didn't have the equipment and facilities to make it happen in the 20s. Now we do. If plasmas are super hot and super excited atoms, the atoms in a Bose-Einstein condensate (BEC) are total opposites

States of Matter

What are the atoms doing in each state?

Physical Change A change that affects one or more physical properties of a substance. Does form new substances. Can often be undone Example melted ice can be placed back in refrigerator.

States of Matter Lutgens and Tarbuck: The Atmosphere

Physical Changes Physical changes can be classified as reversible or irreversible. All physical changes that involve a change from one state to another are reversible. Cutting hair, filing nails, and cracking an egg are examples of irreversible physical changes. 2.1

Chemical Property A property of matter that describes a substance based on its ability to change into a new substance with different properties. Examples: 1 pH - The pH scale measures how acidic or basic a substance is. a measure of the relative amount of free hydrogen (H +) and hydroxyl ions (OH -). The pH of water determines the − solubility (amount that can be dissolved in the water) − biological availability of nutrients (amount that can be utilized by aquatic life). 2. Combustibility - when wood burns 3. Flammability - when fireworks explode 4. Reactivity - when iron Oxidizes (rust)

pH scale

Physical Changes During a physical change, some properties of a material change, but the composition of the material does not change. As gallium melts in a person’s hand, the shape of the sample changes, but the composition of the material does not change. 2.1

Chemical Change A change that occurs when one or more substances are changed into entirely new substances with different properties. Can’t change back under normal conditions (example – vinegar and baking soda). Common Examples: Reactivity – Oxidation (rust) on a bicycle pH (Acid / Base) – Effervescent tablets (Alka Seltzer) and your stomach Flammability – Burnt wood Combustibility - Fireworks