Liquids and SolidsChp 12 pg 362

A. Liquids1. Intro

a. Least common state of matter in universe

b. Can only exist within a relatively narrow range of temps

2. Propertiesa. Definite volume and takes shape of

container b. Particles in constant motionc. Particles closer than gas particles

d. Particles more ordered than w/gasese. Fluid – substance that can flow and take shape of its containerf. Relatively High Density

1) More dense than gas2) Less dense than solid

(typically)g. Can compress slightly – not as much as gash. Pressure equally distributed in all directions

i. Can diffuse1) Caused by browning

movement2) High to low concentration3) Warmer liquids diffuse faster

Diffusion Rate Lab

j. Surface Tension1) Force that pulls adjacent

particles together decreasing surface area (typically sphere)

2) Caused by cohesion

Fiery bubbles

3) Capillary action – attraction of liquid to solid

a) Adhesionb) Goes up until weight of

liquid = gravitational forcec) Causes meniscus, helps

bring water from roots to leaves

Find different tubes to do this with

4) Vaporization – liquid to gasa) Evaporation

i. slow processii. Particles have higher-than-

ave energies which allows them to overcome intermolecular forces

b) Boiling – fast process

5) Formation of Solidsa) Cooling (removing heat) lowers energy of particlesb) Particles become

attracted to each otherc) Form an orderly

arrangement of particlesd) Freezing

B. Solids1. Properties

a. Particles very closely packedb. Intermolecular forces very strongc. Definite volume and shaped. 2 types1) Crystalline (pg 369)a) Most solidsb) Have crystals (geometric

pattern)

2) Amorphous – particles arranged randomly

e. Definite Melting point1) Melting – solid to liquid2) Melting pt – temp at which

melting takes place

f. High density – most dense of all states of matter (typically)g. Can’t be compressedh. Low rate of diffusion

2. Crystalline Solidsa. Can be single crystal or groups of crystalsb. Crystal structure – 3D arrangement of particles

Unit cells of crystalline solids

c. Binding Forces in Crystals (pg 370)

1) Ionic Crystalsa) Hard and brittleb) High melting points

2) Covalent network crystalsa) Large number of

molecules in a networkb) VERY hard and brittlec) non/semiconductors d) Diamonds

Covalent Network (diamonds)

3) Metallic crystalsa) Metal atoms surrounded

by a sea of valence electronsb) B/c of val. Ele they are

very good conductors4) Covalent molecular crystals

a) Covalently bonded moleculesb) Low melting pts

3. Amorphous Solidsa. No natural or regular shapeb. Hold shape for long timec. Some can flow (very slowly)

C. Changes of State1. Equilibrium

a. Two things change at equal ratesb. Changes of state

1) Melting 2) Freezing3) Vaporization4) Condensation5) Deposition 6) Sublimation

c. Things like to be in equilibriumd. If a system is stressed it will regain equilibriume. Stress – concentration, pressure, or temperature

f. How it works (temp)1) Increase temp 2) Causes more to evaporate3) This causes more vapor 4) More vapor = more can

condense5) Equilibrium is reached

g. How it works (concentration)1) Volume is increased2) causes surface area to

increase3) This means more evaporates4) More can condense5) equilibrium is reached

2. Equilibrium Vapor Pressure of Liquida. Volatile liquids – liquids that evaporate easily (ether), weak forcesb. Nonvolatile liquids – evaporate slowly, strong intermolecular forcesc. Depends on only temperature

Demo pg 377

3. Boiling a. Liquid to vaporb. Happens when vapor pressure of liquid = atmospheric pressurec. Boiling pt – temp when equilibrium vapor pressure = atmospheric pressure

How does boiling pt relate to cooking on a mountain?

1) All heat goes to evaporate liquid

2) Temperature doesn’t change as long as pressure is constantd. Energy is used to overcome attractive forces

1) Stronger forces = higher boiling pts

2) Energy stored as PE

4. Freezing and Meltinga. Freezing pt – temp where solid and liquid are at equilibriumb. Melting pt

1) Temp where solid becomes liquid

2) Occurs at constant temperature

Demo pg 380

c. Sublimation and Deposition1) Sub – solid directly to gas

a) CO2

b) Iodine2) Dep – gas directly to solid

5. Phase Diagramsa. Graph of pressure vs. temp and the state of matter

b. Triple pt – pt where solid, liquid, and gas can coexist at same timec. Critical temp – temperature where substance can’t exist as a liquid no matter what the pressure (pg 381)d. Critical pressure – Lowest pressure where substance can exist a liquid at the critical tempe. Critical pt – where critical temp and pressure meet

D. Water1. Importance

a. Cover 75% of earth’s surfaceb. Living things are 70-90% waterc. Chemical reactions need waterd. Frequently a reactant or product

2. Structure of Watera. Made of hydrogen and oxygenb. Bonded by polar covalent bondsc. Molecule is bentd. Angle is 105◦

e. Molecules held together by H bonding

3. Physical Properties of Watera. At room temp

1) Transparent2) Odorless3) Tasteless4) Almost colorless

b. Boils at 100◦ and freezes at 0◦

c. Boiling pt is high compared to most liquids