 Solid  Liquid  Gas  Plasma

 Definite Shape and Volume  Particles are often arranged in repeating geometric patterns to form crystals  Some are composed of particles with no particular order (amorphous solids)

 Definite Volume  Can’t normally be squeezed into a smaller space  Indefinite Shape  Flow and take shape of container

 No definite shape or volume  Molecules can be squeezed together or spread out to fill the space available

 Gas-like mixture of positively and negatively charged particles  Only exists at very high temperatures  MOST of the matter in the universe!!  Around 99%  Ex’s  natural plasmas- lightning, fire  artificial- fluorescent light

1. Solid 2. Liquid 3. Gas 4. Plasma

 All matter is made up of tiny particles (atoms) in constant motion  How MUCH they move depends on how much energy they have  Increased temperature will… increase energy

 Almost all matter expands as it gets hotter and contracts when it cools.  Temperature is a measure of the average kinetic energy of the particles in the object  Theoretically, absolute 0, (0 degrees Kelvin) has no movement of particles Never achieved in a lab

1. Degrees Celsius 2. Average Kinetic Energy 3. Average Potential Energy

 Energy is RELEASED from the substance out to its surroundings  Ex’s- each of these products have molecules with LESS energy than they did before the phase change Freezing (liquid water has more energy than ice) Condensation (gas to liquid) Deposition (gas to solid)

 Energy is ABSORBED by the substance from its surroundings  Ex’s- each of these products have molecules with MORE energy than they did before the phase change Melting (ice has less energy than water) Evaporation (liquid  gas) Sublimation (solid  gas))

 Name the process described and then determine if it is exothermic or endothermic

 The force between two molecules  Holds them together weakly  Stronger in a solid than liquid, etc.

The attractions between molecules are not nearly as strong as the intramolecular attractions that hold compounds together.

They are, however, strong enough to control physical properties such as boiling and melting points, vapor pressures, and viscosities.

The strength of the attractions between particles can greatly affect the properties of a substance or solution.

 Resistance of a liquid to flow is called viscosity.  It is related to the ease with which molecules can move past each other.  Viscosity increases with stronger intermolecular forces and decreases with higher temperature.

Surface tension results from the net inward force experienced by the molecules on the surface of a liquid.

 The state a substance is in at a particular temperature and pressure depends on two antagonistic entities:  The kinetic energy of the particles  The strength of the attractions between the particles

 The heat added to the system at the melting and boiling points goes into pulling the molecules farther apart from each other.  The temperature of the substance does not rise during the phase change.

 Heat of Vaporization: Energy required to change a liquid at its boiling point to a gas.  Also the energy released from the particles when a gas is changed to a liquid!  Heat of Fusion: Energy required to change a solid at its melting point to a liquid.  Also the energy released from the particles when a liquid is changed to a solid!

 heating curve of water animation heating curve of water animation  The total energy absorbed in the heating curve is equal to the total energy released in the cooling curve of water  Melting/freezing pt: occur at same temperature  Boiling/condensation pt: occur at same temperature

 Temperature does not change during a phase change  So, the graphs have 2 main plateau areas where phase changes are occurring

 Explain what happens when a cold glass of water “sweats”

Condensation - gas to liquid a. Particles lose kinetic energy, slow down, and come closer together. b.IF’s become strong enough to make particles merely rotate around each other. c.The energy they lose to turn into a liquid is the heat of vaporization. d. Substance is releasing energy to the surroundings (exothermic)

 Explain what happens when liquid water changes to ice.

Freezing - liquid to solid-. a. Particles lose kinetic energy and slow down. b. Substance releases energy to surroundings (exothermic) c. IF’s b/w particles become stronger than the particles’ motion, so the particles begin merely vibrating in place to form a solid. d. The amount of heat the particles must lose to turn into a solid is called the heat of fusion.