CHAPTER 12

STATES OF MATTER

4 STATES OF MATTER

Gases Liquids Solids Plasma

(Ice Ice Baby Rap) Dance

KINETIC MOLECULAR THEORY

(KMT)- describes the behavior of particles in terms of their motion

Explains the effect of temp. and pressure on matter

KMT video Molecules in Motion Song

Assumptions for KMT- gases

1. Particle size- all matter is composed of small particlesBetween the particles is empty spaceThere are no attractive or repulsive forces

between particles

2. Particle motion- particles are in constant random motionTravel in straight line pathsChange direction upon collisionCollisions are elastic (no net loss of kinetic

energy [KE])

3. Particle energy- kinetic energy (KE) is a factor of mass and velocity of a particleKE= energy an object possesses because of

its motion Formula: KE = 1/2mv2

Depends on mass and velocity

PRESSURE

Dependent on force of collision and the # of collisions

Pressure = force area Atmospheric pressure- (Barometric)

results from the collisions of air molecules w/objects on earthVaries depending on location

Tools for measuring pressure

Manometer = device use to measure pressure of enclosed gas

Barometer = special manometer used to measure atmospheric pressureDeveloped by Torricelli

Aneroid barometer

Standard Atmospheric Pressure

Average pressure at sea level = 760 mmHg (millimeters of mercury) Units for pressure:

Pascal (Pa) = 1 Newton m2

1000 Pa = 1kPaStandard atmospheric pressure = 101.3 kPa

Also known as 1 atm (atmosphere)

Pressure Conversion Factor

101.3 kPa = 1 atm= 760 mmHg = 760 torr = 14.7 psi

Example:

216.9 kPa = _____________ mmHg

763 mmHg = ______________kPa

216.9 kPa

101.3 kPa

760 mmHg 1627 mmHg

763 mmHG

760 mmHg

101.3 kPa 102 kPa

TEMPERATURE DEFINITION: measure of the average KE

of the particles in a substance (> temp. = > KE)

If you have 2 substances at same temp., they must have the same average KE, so the molecule w/the less mass will move faster

Ex: O2 and H2 at 20°C

32 g/mole 2 g/mole

-so H2 has the > velocity

ABSOLUTE ZERO

Temperature at which the motion of particles ceases (stops moving)

Absolute zero = -273°C

KE = 0

KE

Temp. °C

0 100-273

Absolute zero

Spitzer Space Telescope Launched August 24, 2003 With this new infrared telescope, only the science instrument

chamber and a compact cryostat will be cold at launch, chilled to about 1.5 Kelvin (-272 Celsius, or -457 Fahrenheit). Following launch from Cape Canaveral Air Force Station in Florida, the spacecraft cooled in the deep recesses of space for about five weeks. The observatory uses the vapor from the boil-off of its cryogen fluid to cool the telescope assembly down to its optimal operating temperature of 5.5 Kelvin (-268 Celsius, or -450 Fahrenheit).

cryogen depletion date 5/15/09 (now in warm mission- two of its arrays still working)

James Webb

Supernova remnent (star death)

Vega (dust cloud around)

A Joke Break…

Q: What did the thermometer say to the graduated cylinder?

A: "You may have graduated but I've got many degrees"

Ha, Ha, Ha, again I crack myself up.

TEMPERATURE SCALES Farenheit- 32°F= freezing water; 212°F=

boiling water Celcius- based scale on freezing point of

water = 0°C; boiling = 100°C Kelvin- based on absolute zero;

0 K = -273°C

(a change of 1 degree on K scale is same on °C)

Conversion factor K = °C + 273

Example: 25 ° C = ___________K

400 K = ____________ °C

298

127

Use for temperature:

Determine direction of energy flow When a cool object (less KE) is in contact

w/a warmer object (higher KE) the energy of the warmer object will transfer to the cooler until the KE is equal or same temp.

Heat (em cee delta tee song)

The energy transferred due to a temp. difference

Physical and chemical changes are accompanied by energy changes

Heat (Q) – energy transferred from a hotter object to a cooler object due to a temp. difference

Exothermic- released energy; gives off heat or light

Endothermic- absorbs energy; cool to the touch

LAW OF CONSERVATION OF ENERGY ENERGY CAN BE CONVERTED FROM

ONE FORM TO ANOTHER BUT IT IS NOT CREATED NOR DESTROYED

Activation energy = the minimum amount of energy needed to get a reaction started

UNITS FOR HEAT

Joule (J)- quantitative measurement of an energy change or heat

English system uses a calorie (cal) Conversion factors

1 cal = 4.18 J1000 cal = 1 Cal (food value) = 1 kcal

little”c” big “C”Ex. 1 tic tac = 4180 J or 1 Cal

Orange Juice

340 kJ (80 Cal)

SPECIFIC HEAT Constant

The heat needed to raise the temp. of 1 g of a substance 1°C or 1 K

Represented with the letter “c” Unit= J/g°C Ex: c water = 4.18 J/g°C

MEASURING ENERGY CHANGES

CALORIMETER- device used to measure energy changesUsually contains waterMeasures heat absorbed or releasedFollows Law of conservation of Energy

1. Formula for heat Q = m c T Heat lost or gained = (mass in grams)(specific heat constant)(change in

temp)

How much heat is needed to heat up 145g of water from 25.0 C to 95.0 C? Specific heat of water= 4.18 J/g C.

2. Finding specific heat of unknown substance

Heat lost = heat gained by water Q lost = Q gained

Q lost = mcT Q gained = mcT so, mcTlost = mcTgained

A piece of metal with a mass of 35.0 g and a temperature of 100.0 C is placed into 105.0 g of water at a temperature of 25.0C. After the metal cools the final temperature of the system is 31.5 C. What is the specific heat of the metal?

Lab- Specific Heat

Data (w/ units) Calculations: (do for each metal)

1. Mass of water (data #3- data #2)2. Change in temp. water (data #6- data #5)3. Change in temp metal (data #4 – data # 6)

mcTlost = mcTgained

(data #1) c (calc #3)=(calc # 1) 4.18 (calc #2) (solve for c) % Error= O (above) – A x 100 A Also: Questions & Conclusion

What is the pressure in atmospheres if the pressure is 742 mm Hg?

If a book with a force or weight of 25 N is laying flat on a table covers a surface that is .20 m by .35 m, what is the pressure it is applying to the table?

A piece of unknown metal with mass of 14.9 g is heated to 100.0 C and dropped into 75.0 g of water that was at 20.0 C. The final temperature of the system is 28.5 C. What is the specific heat of the metal?

Lab- Calories of FoodHow to use the Lab Pro Data (w/ units) Calculations (one for each food item)

1. Change in temp (data 7- data 8)2. . mass of water (data #4- data #5)

3. Heat lost by food= Heat gained waterQ lost= mc Δ t (water)

Q = (calc. #2) (4.18) (calc #1)

4. Convert heat lost (joules to cal)Calc #3/ 4.18

5. Mass of food burned(data #1- data#2)

6. Heat lost by 1 gram of foodcalories (calc #4) / mass of food (calc #5)

7. % ErrorCalc #6- accepted value x 100

Accepted value

Questions (1,2) and conclusion

STATES OF MATTER

Describing the kinetic theory as it applies to the states of matter Dance

INTRAMOLECULAR FORCES

Attractive forces that hold particles together in ionic or covalent bonds (intra= within)

INTERMOLECULAR FORCES

Forces of attraction between particles (holding similar particles close together like in a solid or liquid)

Intermolecular forces video Types:

van der Waals Dispersion forces Dipole-dipole forces (polar molecules) Hydrogen bond (special type of dipole-dipole force)

GAS Independent particles moving in straight

lines Change direction with collision Travel randomly Assume shape and volume of container Large amount of empty space No attraction force compressible

Gas video

Gas properties:

Fluidity- gas particles glide and flow past each other

Expansion- fill any container Compressibility- can decrease volume Diffusion- spontaneous mixing of 2 gases;

flow until evenly dispersed; flow from area of higher concentration to lower

Graham’s Law of Diffusion- proportion comparing diffusion rate

Rate A = molar mass B Rate B molar mass A Ex: HCl and NH3Molar mass = 36.5 molar mass = 17.0

Rate NH3 = molar mass HCl

Rate HCl molar mass NH3

= 36.5 17.0 = 1.5

So NH3 diffuses 1.5 x faster

LIQUID

Properties video Form of matter that flows, has constant

volume and takes the shape of its container

Particles are in motion but slower than gases (slip/slide motion)

Particles are held together by weak intermolecular forces (don’t have enough KE to break away from the attraction)

Reduced amount of empty space

Properties of Liquids

Density and compressionLiquids are denser than their gas phaseLiquids can be compressed, but an enormous

amount of pressure must be applied to reduce the volume by just a small proportion

Fluidity Liquids flow and can be diffused (yet not as well as

gases)

Viscosity Measure of a liquids resistance to flow (stronger the

attractive force, the higher the viscosity) Viscosity increases w/a decrease in temp. (cold oil

doesn’t flow well as warm) Molecules w/longer chains have higher viscosity

Surface Tension

A property of liquid surfaces that causes the surface layer to behave like a thin elastic 'skin'.

Molecules in a liquid have attractive forces that hold them together. Molecules on the surface are attracted to molecules from all sides and below, but not from above .Surfactants- (soap/detergent); compounds

that lower the surface tension of water

Capillary action

Force of adhesion between a liquid and a solid

Ex: meniscus in graduated cylinderCellulose fibers in paper towel wicking up water

(water suspension)

SOLID

Properties video-solid Particles are packed against one another

in a highly organized fashion Move much slower, don’t slide from place

to place but vibrate & rotate about fixed points (straight line paths w/neighbors)

Definite pattern in arrangement of particles

Definite shape and definite volume Dense and incompressible

Crystals

All true solids are crystals A substance in which the particles are

arranged in an orderly, geometric, repeating pattern

Have flat faces that meet at definite angles

Crystal Structure

3-D pattern of small units repeating over and over

Determined by the type of bond between particles

Crystal Systems

Cubic- salt

Tetragonal

Orthorhombic

Rhombohedral

monoclinic

Triclinic

Hexagonal- water, quartz

Water Example (hexagonal)

Water molecules are further apart in solid state than liquid (solid-> less dense)

Water is different because of hydrogen bonding. A water molecule is made from one oxygen atom and two hydrogen atoms, strongly joined to each other with covalent bonds.

Water molecules are also attracted to each other by weaker chemical bonds (hydrogen bonds) between the positively-charged hydrogen atoms and the negatively-charged oxygen atoms of neighboring water molecules. As water cools below 4°C, the hydrogen bonds adjust to hold the negatively charged oxygen atoms apart.

Amorphous Materials

Appears to be a solid but its particles have a disorderly arrangement (no crystal form)

Ex: glass- no defined melting point, super cooled liquid

When shattered breaks at irregular angles, where a crystal when shattered will break along the unit cell

Butter- also super cooled Plastic

METASTABLE- substance that can occur in long-lasting amorphous form (crystallization will eventually occur but not in your lifetime- millions of years)

PLASMA

Occurs when matter is heated to a very high temperature > 5000ºC

The collisions have so much KE and are so violent that electrons are knocked away from the atoms

Plasma is those electrons and the left over positive ions from the collisions

Behaves generally like a gas

PARTIAL PLASMA- Only a few of the atoms are ionized Neon signs, lightning, fluor. lights

Highly ionized plasma= (50000 K- 100000K)Stars, sun

PHASE CHANGE

Occurs whenever a physical state of a substance changes (at the melting and boiling pts.)

Ex: phase change of water

(0°C- melt; 100°C boil)

On the graph following, get a leveling off at phase change pts because all of the energy is going into breaking the attractive forces (intermolecular)not raising temperature

Physical state depending on bonding structure (ionic, covalent)

SOLID

GAS

LIQUID

*SUBLI

MATIO

N

DEPOSITIO

N

*MELTING

FREEZING

CONDENSATIO

N*VAPO

RIZATO

N* Requires energy Releases energy

Sublimation = goes directly from solid to gas (dry ice, moth balls, Glade plug in)

Deposition= goes from gas to solid frost

PHASE DIAGRAMS

p.429-430 picture Diff for each substance because each

substance has different boiling and freezing point

Variables that control the phase of a substance are temp. and pressure

Phase diagrams show the relationship between temperature and pressure

Triple point = temp. and pressure at which all 3 phases can coexist

Critical Point- liquids can no longer exist