“Gravitation is not responsible for people falling in love.” Albert Einstein Bellringer Why does a gas take the shape and volume of its container? Why does a liquid take the shape but not the volume of its container?

SOLiDS How are the structure and properties of solids related? ORDERLY ARRANGEMENT of particles FIXED LOCATIONS of particles

Phase Differences Solid Solid – definite volume and shape; particles packed in fixed positions; particles are not free to move Liquid Liquid – definite volume but indefinite shape; particles close together but not in fixed positions; particles are free to move Gas Gas – neither definite volume nor definite shape; particles are at great distances from one another; particles are free to move

Crystalline Solids highly regular arrangement of particles

Amorphous Solids disorder in their structures (glass and plastic).

Think about it… Why does a solid have a definite shape and a definite volume?

Water Water exists on our planet in three states. Ice, water, and water vapor What causes water to be in one phase or another?

ENERGY When energy is added to a substance that energy causes the particles in the substance to move faster and farther apart. What happens to the particles when energy is taken away from a substance?

Phase Change Energy content is responsible for the different phases of matter. Matter can be made to change phase when energy is added to or taken away from a substance.

ENDOTHERMIC: heat/ energy is ABSORBED EXOTHERMIC: heat/energy is RELEASED

Block of Ice to Steam Block of Ice to Water Vapor Things to consider: What does the motion of the particles look like? When are they changing phases? What is the temperature when they change phases? Do all of them change phases at once?

Melting- Solid to Liquid the substance absorbs heat energy. Melting Point –Water 0° C. –Table salt 801° C. –Diamond 3700° C. What happens to the particles?

melting

Freezing- Liquid to Solid a substance loses heat energy. The freezing point of a substance is equal to the melting point! What happens to the particles?

Phase Change Graph

Freezing melting

Vaporization- Liquid to Gas substance absorbs heat energy. Vaporization occurring at the surface of a liquid is called evaporation. What happens to the particles?

Evaporation- a Cooling Process As water in the perspiration evaporates from your skin it absorbs and carries away heat energy from your body.

Boiling When all the particles in the liquid have enough energy to vaporize, the liquid begins to boil The particles travel to the surface

Boiling Point Boiling Point – temperature at which a substance boils. –Water 100° C. –Table salt 1413° C. –Diamond 4200° C. What is the difference between evaporation and boiling?

Phase Change Diagram

Freezing meltingvaporization

Condensation- Gas to Liquid A substance in the gas phase that loses heat. What’s going on here?? Why do we have condensation on a cold glass?

Condensation Water vapor in surrounding air loses heat energy when it comes in contact with the cold glass. Water vapor condenses and becomes liquid drops of water.

Phase Change Graph

condensationFreezing meltingvaporization

Sublimation – Solid to Gas surface particles of a solid change directly into a gas.

Sublimation 2Xj0ohttp:// 2Xj0o

Phase Change Graph

condensationFreezing meltingvaporization Sublimation

Deposition – gas to solid You may notice this in the cold winter with snow. The snow does not melt, but slowly disappears. Dry ice goes directly from solid carbon dioxide to gas.

condensationFreezing meltingvaporization Sublimation Deposition

Energy in Phase Change

Phase Change Phase Change Diagram in Water

Temperature Comparisons Boiling Point of H 2 O 212  F 100  C Melting Point of H 2 O 32  F 0  C Freezing Point of H 2 O 32  F 0  C

Phase Diagram

Triple Point: only set of conditions in which all three phases can exist at once