Lecture: Phases of Matter “jane chen: a warm embrace” that_saves_lives.html that_saves_lives.html

What is “phase” of matter? What controls phase of matter? Draw a picture of YOUR favorite phase of matter, and say why it is?

1. Matter is defined as: ? mass and volume 2. Properties of matter: two categories: A. Physical: how an object appears/to change 1. mass: ? 2. volume: ? 3. density: ? 4. color: ? 5. shape: ? 6. hardness:? 7. texture:? 8. phase change:? B. Chemical: how it changes into a new substance: reactivity (w/bonds broken or formed)

3. Characteristic properties: are indicators of substances (not an indicator of an object) like DNA is an indicator of species or organism: A. freezing point (phase change) B. melting point (phase change) C. boiling point (phase change) D. density E. solubility F. flammability 4. Phases of matter: same substance w/ different amounts of energy (molecule spacing will change too): 4 phases: solid, liquid, gas and plasma

A. Solid 1. definite shape and definite volume 2. very little movement: Brownian motion(?) only: -due to very little kinetic energy of e- 3. frozen in space: - does this mean cold? - molecules locked in place: frozen -not always cold: your desk, hair? 4. lowest energy state, why?

B. liquid: 1. definite volume 2. shape fits container up to a level 3. molecules flow: low viscosity (= resistance to flow: honey/oil high viscosity) 4. random molecules arrangement 5. medium amount of energy

C. gas: 1. no definite shape or volume 2. occupies full shape of container 3. high energy: lots of molecular motion 4. gravity keeps atmospheric gases around the Earth

5. gas laws: a. Boyles’ law: as pressure on a gas increases, its volume decreases: P: V (inverse relationship) -eardrums, submarines, balloon at the bottom of a pool b. Charles’ law: as temperature on a gas increases, volume increases: T: V (direct relationship) -car tires, balloon in microwave

D. plasma 1. highest state of energy 2. found in stars, lightning, neon lights 3. most common/abundant phase of matter in the universe, why? 4. atoms begin to break down: e- disassociate from nuclei = ionize

5. Phase change (phase molecular model demo) A. energy in the form of heat (kinetic energy) determines the phase (particle excitement) -intermolecular forces (the molecule to molecule “glue”: keeps shape of substance) are broken and the substance begins to form a new phase when heated -the atom-to-atom bonds are NOT broken: ie H 2 O? - this is why water is liquid at room temperature and gold is solid at room temperature: - their intermolecular forces are different, gold’s is much stronger. - how do the intermolecular forces of mercury compare to water (think mercury thermometer)?

B. phase change is a physical change: still the same “stuff”: ice  water  steam C. melting point: - temperature from solid to liquid; - freezing point: temperature from liquid to solid - both of these are the same temperature for the same substance, just… -opposite energy: going into/out substance D. usually when a solid melts its volume increases, not so with water or bismuth: this is extremely abnormal; -this is why ice cubes and icebergs float and lakes do not freeze solid.

E. vaporization: changing from liquid to gas F. evaporation: vaporization at the surface of a liquid: breaks intermolecular bonds, releasing energy: sweating? G. boiling point: temperature of change from liquid to gas: steam. Also depends on the pressure of the air at the surface (bp of water at Boulder (94 C) is less than at sea level (100 C): less atmospheric mass: ie dog pile ) H. condensation point: temperature of gas to liquid: drips on outside of soda cans I. sublimation: change from a solid to a gas w/o liquid phase: dry ice, iodine, ice cube loss in freezer J. absolute zero: when all molecular motion stops, even electrons! Thus no Brownian motion. - Bose-Einstein condensate - 0 degrees Kelvin (-273 C)

Heating/cooling curve: note when 2 phases are present: temp does not change w/ more energy: it’s a horizontal line: Fz/mlt pt Bpt/cond pt

Draw a CO 2 sublimation curve (label axis too):

Sublimation curve (dry ice): solid gas Solid and gas Note: when two phases are present at the same time, the line looks like what?

K. atoms have kinetic energy ?: Brownian/molecule motion L. temperature is a measure of: kinetic energy - what is your temperature in Celsius? And what is it actually measuring? M. phase change maintains the chemical make- up of a substance while altering the physical arrangement due to an energy change: it’s still the same stuff but it looks different