1. Compare solids, liquids, and gases.
Do Now:
Compare solids, liquids, and gases.
At room temperature, why is water typically found as a liquid, carbon dioxide as a gas, and carbon as a solid?
Try water and cu on pg

2. Solid Liquid Gas Not very compressible Highly compressible
High denisty
High density
Low density
Definite volume
Fills container competely
Retains its own shape
Assumes shape of container
Motion limited to vibrational movement
Slow diffusion – particles can slip past each other
Rapid diffusion
Low expansion on heating
High expansion on heating

3. Why are the properties of each state so different?
Force of attraction between atoms, ions, or molecules. A solid has the strongest attractive forces, a gas has the weakest (negligible) attractive forces.

4. Gases…
What are some unique properties or physical behaviors of gases that differ from the other states?

5. To help us understand gas behavior we can use
The Kinetic Theory
a model
states that all forms of matter are made up of tiny particles that are in constant motion

6. Kinetic Molecular Theory
A gas consists of small particles that have mass.
The particles are far apart from each other (volume of gas molecule is insignificant).
No attractive or repulsive forces exist between the molecules.
Proposed explanation of properties described/observed

7. Kinetic Molecular Theory
Gas particles are in constant, rapid and random motion. They move in straight paths and fill their container
Collisions of gas particles with each other or with the walls of the container are perfectly elastic. Kinetic energy is conserved.
Proposed explanation of properties described/observed

8. When gas molecules collide with other molecules, their container, or any object…
They apply a force over an area
PRESSURE!
ONE SMALL MOLECULES NOT SO MUCH BUT BILLIONS ADD UP
VACUUM – NO OR VERY VERY FEW GAS PARTICLES PRESENT, NO COLLISIONS, NO PRESSURE

9. Pressure units Pascal (SI unit) = 1 N/m2 Other pressure units… kPa
atmospheres
mm Hg
psi (lb/in2)

10. Atmospheric Pressure
Force exerted on you by the weight of tiny particles of air (air molecules).
Air molecules are moving, collide with things, apply force per area … Pressure!
Standard atmospheric pressure is 760 mmHg or 1 atmosphere (1 atm)
It is dependent on elevation. At high elevation, air pressure is lower.
20 miles of air (atmosphere is 20 mi thick)stacked up over your head
Demo  Fill a paper cup to the brim with water.Now place a piece of cardboard over the top of the cup and invert it.Think about what might happen:
If there is no atmospheric pressure, the weight of the water should push down against the cardboard causing water to go all over the place.
If there is atmospheric pressure, it should exert a bigger force on the cardboard than the water does and the cardboard should "stick" to the bottom of the glass.
though the air causing the pressure is above you, the air pushes with equal pressure on all sides of your body. This is known as "Pascal’s Law" and is true for any fluid (a fluid is anything that "flows" which can be any gas or liquid). . As the air pushes in on our heads and our sides, our heads and sides push back out the same way and we don’t feel like we’re being squished. A marshmallow pushes outward with 14.7 psi and so the inward pressure is balanced by an outward pressure.

11. Atmospheric Pressure can be measured with a barometer
Does mercury have to be used?
Can water be used?
How would the barometer and pressure reading be affected?
a rising barometer means wind, frost, or clear skies, while a falling barometer indicates coming storms. A steady barometer might mean precipitation or sun.

12. What does temperature measure?
The average kinetic energy of the molecules
When a sample absrobs energy, some energy is stored as potenetial energy, does not raise the temperature of the molecues, remainder sppeds up the particles – the particles in any collection of mateiral have a wide ranges of kinetic energy, most have nergy somewhere in the middle – average kinetic energy

13. Absolute Scale
Must be used to describe kinetic energy of molecules and their motion
ºC (Celsius) = K ( Kelvin)

14. Liquids Particles are attracted to each other (has a definite volume)
Particles are free to move past each other (liquid flows) in addition to vibrating
These movements contribute to the average kinetic energy of the molecules.
Yesterday we observed various properties of liquids. Today we are going to understand a few more liquid concepts.

15. Compare evaporation and boiling
Vaporization ( liquid > gas)
Evaporation occurs at the surface.
Boiling occurs in the body of the liquid. Depends on atmospheric pressure.
It’s a cooling process (sweating)

16. EVAPORATION (a surface phenomenon)
Gaseous molecule will collide with the liquid surface and if kinetic energy sufficiently low it will be captured and return to liquid phase
Water molecules at the surface overcome IM forces and escape into the vapor phase
Vapor Pressure
Dynamic Equilibrium

17. Boiling Normal Boiling Point
Boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the atmospheric pressure surrounding the liquid
Normal Boiling Point
the temperature at which a liquid's vapor pressure equals one atmosphere (standard pressure)

18. Solids
Crystals – rigid body where particles are in a highly ordered, repeating pattern.
They are seven crystal systems classified by shape
Unit cell is the simplest repeating unit that generates the crystal
What shapes do you see

19. Some arrangements of atoms…

20. What keeps Salt, NaCl, together? - - -
Lead, Pb, together? - - + - +
Ionic compounds are held together by ionic bonds, positive ions attracted to negative ions
Metals are held together by metallic bonds, sharing of valence electrons among fixed positive ions
Mercury-mercury bonding is very weak because its valence electrons are not shared readily. (In fact mercury is the only metal that doesn't form diatomic molecules in the gas phase).
Heat easily overcomes the weak binding between mercury atoms, and mercury boils and melts at lower temperatures than any other metal. The thin valence electron sea makes mercury's ability to conduct electricity and heat much poorer than expected for a metal at that position in the periodic table.
Why is the pair of 6s electrons so inert? The s electrons are able to come very close to the nucleus. They swing around very massive nuclei at speeds comparable to that of light. When objects move at such high speeds, relativistic effects occur. The s electrons behave as though they were more massive than electrons moving at slower speeds. The increased mass causes them to spend more time close to the nucleus. This relativistic contraction of the 6s orbital lowers its energy and makes its electrons much less likely to participate in chemistry- they're buried deep in the atomic core.
Why doesn't this effect make gold and thallium liquid too? Let's compare the electronic configurations for gold, mercury, and thallium: AtomAverage atomic massGround state configurationAu [Kr] 4d10 4f14 5s2 5p6 5d10 6s1Hg200.59[Kr] 4d10 4f14 5s2 5p6 5d10 6s2Tl [Kr] 4d10 4f14 5s2 5p6 5d10 6s2 6p1All three atoms have very low energy 6s orbitals. But the gold 6s orbital is only half filled. Accepting an electron into that low energy orbital will lower energy overall, and metal-metal bonding is expected to be strong as a result. Still, the 6s electron is held tightly and gold's reputation as a 'noble metal' comes from its inertness.

21. Network Crystal Carbon
Solids that contain strong directional covalent bonds to form a solid that might be viewed as a “giant molecule”.
Carbon
Graphite
Diamond
Allotrope – form of an element differing in crystal or molecular structure
NC is another crystalline structure. Another NC are silica compound with SiO2 or SiO4 interconnected (Rocks, soils, clays, quartz)

22. Diamond Hardest naturally occuring substance
Used in industrial cutting implements
High pressure( atm at 2800ºC) converts graphite to diamond. HT needed to break bonds Insulator (no delocalized electrons ) Each carbon is bonded to four atoms in a tetrahedral.
Synthetic diamonds are often yellowish in color (rarely used for gem purposes, more commonly used as diamond grit for industrial purposes. Modern synthesis of thin film diamond has other industrial applications).
A 5 mm diamond (0.5 carat) takes over a week to grow. Synthesis requires:
high pressure high temperature a special apparatus Synthetic diamonds can sometimes be distinguished from natural diamonds by the presence of flux inclusions (Ni, Al or Fe).

23. Graphite Slippery (used as a lubricant) Conductor of electricity
Pencil “lead”
Sea of electrons – four electrons participate in bonding (one delocalized – p orbital – with pi bonding) –trigonal planar arrangement. Has very strong bonding within layer but little bonding between layers (valence e are all used to form sigma and pi bonds). Layers can slide past one another

24. Fullerene (aka Buckyballs)
Discovered in 1985
Named after Richard Buckminster Fuller, an architect, who designed geodesic domes
The basic C60 structure consists of 60 carbon atoms that link together to form a hollow cage-like structure.
Because it’s hollow other molecules can be captured in itAlthough fullerenes have been found in seemingly simple things as candle soot, the most common technique for the production of fullerenes involves establishment of an electric arc between two carbon electrodes. Under these conditions, the energy from the arc is dissipated by breaking carbon from the surface. The carbon cools in the inert atmosphere and forms buckyballs. This technique however, is not scalable to be able to produce commercial quantities.
The first commercial production technique was the Kratschmer-Huffman arc discharge technique, from 1990 which used graphite electrodes. This technique primarily produces C60 and C70 but could be modified to produce larger fullerenes. Some potential applications for fullerenes include:
Superconductors
Lubricants
Catalysts due to their high reactivity
Drug delivery systems, pharmaceuticals and targeted cancer therapies.
Hydrogen storage as almost every carbon atom in C60 can absorb a hydrogen atom without disrupting the buckyball structure, making it more effective than metal hydrides. This could lead to applications in fuel cells.
Optical devices
Chemical sensors
Photovoltaics
Polymer electronics such as Organic Field Effect Transistors (OFETS)
Antioxidants
Polymer additives
Cosmetics, where they “mop up” free radicals.

25. Amorphous Material Substance that lacks order
Does not have a sharply defined melting point
As heated, gradually softens and flows
Upon cooling, it flows more and more slowly
Viscosity (resistance to flow) increases
Examples: Glass and butter

26. Do Now: Solid Liquid Gas Name each phase change.
Indicate if endothermic or exothermic process

27. Phase Diagram