3.1 Solids, Liquids, and Gases 1. Kinetic Theory = all particles of matter are in constant motion 2. States of Matter A. Solids strong attractions between particles in a solid Usually have an orderly arrangement of particles Particles vibrate around fixed locations Have a definite shape and volume

B. Liquids Particles in a liquid are not as affected by forces of attraction Particles are close together, but their arrangement is more random The average speed of a particle is faster than in a solid Liquids have a definite volume but not shape

Particles have a lot of space between them, arrangement in random http://www.media.pearson.com.au/schools/cw/au_sch_whalley_sf1_1/int/matter.html http://www.media.pearson.com.au/schools/cw/au_sch_whalley_sf1_1/int/2_slg.html C. Gases At room temperature, particles in a gas move approximately 450 m/s on average Particles have a lot of space between them, arrangement in random Particles are unaffected by other particles unless they collide Forces of attraction can be ignored Have neither a definite volume nor shape

D. Plasmas Exist at high temperatures Form 99% of all matter in the universe Occur when atoms are stripped of their electrons Are gases consisting of nuclei and electrons

Force distributed over an area P = F/A More force, more pressure Gas law lab http://intro.chem.okstate.edu/1314F00/Laboratory/GLP.htm 3.2 The Gas Laws 1. Pressure Force distributed over an area P = F/A More force, more pressure More area, less pressure Measured in pascals (Pa) or kilopascals (kPa) 2. Gas Pressure Caused by collisions between gas and walls of the container

3. Volume If you decrease volume then you: increase number of collisions increase pressure

4. Boyle’s Law If temperature is kept constant then pressure is inversely proportional to volume PV = constant P1V1 = P2V2

5. Temperature If you increase temperature then you: increase kinetic energy increase speed of particles increase number of collisions increase pressure

6. Charles’s Law If pressure is kept constant, then volume is directly proportional to temperature (in Kelvin) V/T = constant V1/T1 = V2/T2

7. Number of Particles If you increase the number then you: increase collisions increase pressure

If the number of particles is kept constant then: Vacuum, Handboiler, Soda can Cartesian 8. Combined Gas Law If the number of particles is kept constant then: PV/T = constant P1V1/T1 = P2V2/T2

May be exothermic or endothermic Phase change lab 3.3 Phase Changes When a substance changes from one state of matter to another, reversible May be exothermic or endothermic Exothermic = energy released Endothermic = energy absorbed Involves NO change in temperature Energy is involved in breaking or forming bonds

A. Melting (solid to liquid) Endothermic Heat of fusion = energy absorbed as a substance melts (J/g) Used to break bonds/attractions between molecules, NOT to raise temperature Heat of fusion lab

B. Freezing (liquid to solid) Exothermic Freezing water makes rigid bonds and makes ice less dense

C. Vaporization (liquid to gas) Endothermic Heat of vaporization = energy absorbed as a substance vaporizes (J/g), used to break bonds Vapor pressure = pressure caused by collisions of vapor with walls of a container

1. Evaporation Occurs at the surface of a liquid Below the liquid’s boiling point Some particles have enough energy to escape the liquid 2. Boiling Occurs below the surface Some particles have enough energy to escape the attraction of nearby particles and form a bubble of vapor that rises Occurs when vapor pressure equals atmospheric pressure

D. Condensation (gas to liquid) Exothermic (ex. Dew) E. Sublimation (solid to gas) Endothermic (ex. Dry ice) F. Deposition (gas to solid) Exothermic (ex. Frost on window)

Dippy Duck, vacuum boil