chapter 12 states of matter. 4 states of matter gases liquids solids plasma (ice ice baby rap)ice...
TRANSCRIPT
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