Sunday, February 28, 2010

Friday, 2/26/10

In class we went over the answers to the homework #12 which are:
  1. a. 105kPa b. 5.0 mL c. 42.4kPa d. 6.78 x 10^-3 dm^3 e. 1.24 atm f. 1.5 m^3
  2. 8.0 m^3
  3. 2.5 x 10^-2 atm
  4. 8.01 x 10^-2 dm^3
  5. a. 234 K b. 1.2 dm^3 c. -269.17 C d. 8.10 x 10^-2 L e. 487 cm^3 f. 68.2 m^3
  6. 1.45 cm^3
  7. -40.2 C
This weekend's homework is the worksheet she handed out.

Thursday, February 25, 2010

2-25-10

The one question we did today in class:

(rate of effusion H)/(rate of effusion O)= Squareroot(O's molar mass)/Squareroot(H's molar mass)

AKA: H has a higher rate of effusion, because O is bigger.

Wednesday of Next week is when the test will be

The Homework is Pg. 390: 7-11, 18-26


GETCHU SUM BLOG POINTS

Wednesday, February 24, 2010

where is the blog??

Is anyone else wondering where the blog might be, because i thought Dr.B said she would have something we would comment on up in seventh period?

Tuesday, February 23, 2010

Pre-lab stuff + parts of Sec 3 and 4 notes

At the begining of the lab Dr. B will give us the barometric pressure, but not the units we need, we will have to convert it as part of the lab.
During the lab there will be no chewing on any substances. HCl will be used during the lab and it will burn your skin.
......................................................Missed some info...................................................
Add HCl the the tube then hold the tube with HCl at an angle when squeezing the water slowly into the tube, try not to let the water and HCl mix because it will cause the reaction to go slower. When putting the capper and magnesium in the tube put it in close to the top and not far in the tube. Then you put your finger over the top of the tube and flip it over and into the beaker with water. It should start to bubble and gas will start to form at the what used to be the bottom of the tube, now the top.
NOTES - CH11 sec 3 cont.
The Ideal Gas Law cont.
The Ideal Gas Constant cont.

  • The calculated value of R is usually rounded to 0.0821(L x atm)(md x k)
  • Dr. B wants Rto equal 0.08206
  • use this value in ideal gas law calculations when the volume is in liters, the preasure is in atmospheres, and the temp is in kelvins
  • The ideal gas law canbe applied to determine the existing conditions of a gas sample when three of the four values; P,T,V, and n; are known
  • be sure to match the units of the known quantities and the units of R
  • Sample problem 1: what is the pressure in atmospheres exerted by a 0.500mol smple of nitrogen gas in a 10.0 L container at 298K?........P=nRT/V..........P=(0.500mol)(0.08206L x atm)(298K)/10.0L 122atm

Graham's Law of Efusion

  • Rates of effusion and diffusion depend on the relative velocities of gas molecules. the velocity of a gas varies inversely with the square root of its molar mass.
  • recall that the average kinetic energy of the molecules in any gas depends on the temperature and equalys(1/2)mv^2
  • for 2 different gases, A and B, at the same temperature, the following relationship is true 1/2 MaVa^2= 1/2 MbVb^2
  • from the equation relationg the kinetic energy of two different gases at the same conditions, one can derive an equation relating the rates of effusion of two gases with their molecular mass. Rate of effusion of A/rate of effusion of B= square root of Mb/ square root of Ma
  • this equation is known as Graham's law of effusion which states that the rates of effusion of gasses at the same temperature and pressure are inversely proportional to the square roots of their molar mass

Monday, February 22, 2010

Boom

  • You can use the volume ratios as conversion factors in gas stoichiometry problems as you would mole ratios.
  • Ideal Gas Law
  • You have learned about equations describing the relationships between 2 or 3 of the 4 variables - Pressure, Volume, Temperature and number of moles - needed to describe a sample at a time.
  • All of the laws you have learned thus far can be combined into a single equation, the IDEAL GAS LAW: the mathematical relationship among pressure, volume, temperature, and number of moles of a gas.
  • R is a constant
  • PV=nRT
  • In the equation representing the Ideal gas law, R = idea gas constant
  • Its value depends on the units chosen for pressure, volume, and temperature in the rest of the equation.
  • Measured values of P, V, Temp., and n for a gas at near-ideal conditions can be used to calculate R
  • R = 0.082058
  • P.S. I left the floor open for comments containing some of the notes, I purposely left out some bullet points.

Friday, February 19, 2010

Notes from Friday, Feb. 19

Homework for this weekend: Read ahead in the chapter. Print out the ideal Gas Law Constant Lab and do the pre-lab for Monday.

  • Boyle's Law, Charles' Law, and Gay-Lussac's Law can be combined into a single equation that can be used for situations in which temperature, pressure, and volume all vary at the same time.
  • This is the combined gas law, PV/T=k, or P1V1/T1=P2V2/T2.
  • Each gas law can be derived from the combined gas law when the proper variable is kept constant.
  • Sample Problem F can be found in your book.
  • In the early 1800s, French chemist Joseph Gay-Lussac observed that 2L hydrogen can react with 1 L oxygen to form 2L water vapor.
  • This reaction shows a simple 2:1:2 ratio in the volumes of reactants and products. This same ratio applies to any volume proportions.
  • Gay-Lussas's law of combining volumes of gases (that's a mouthful) states that at constant temperature and pressure, the volumes of gaseous reactants and products can be expressed as ratios of small whole numbers.
  • 1811: Avogadro explained Gay-Lussac's law of combining volumes of gases without violating Dalton's idea of indivisible atoms.
  • Avogadro reasoned that, instead of always being in monoatomic form, when they combine to form products, gas molecules can contain more than one atom.
  • Avogadro's law: equal volumes of different gases contain the same number of molecules, at given pressure and temperature. Also, gas volume is directly proportional to the amount of gas at a given temperature or pressure. V=kn.
  • Dalton had guessed that the formula for water was HO, but Avogadro's reasoning established that water must contain twice as many hydrogen atoms as oxygen atoms because of the volume ratios in which the gases combine.
  • Ergo, Avogadro's idea of diatomic gases was consistent with all other knowledge and laws.

Thursday, February 18, 2010

2/18.10

Today in class we went over Tuesday nights homework and took notes. Also, there is a quiz tomorrow on Chapter 10 the section is unknown so know all of them. For those that qualify: The make up test will be on the 24th after school.

Tuesday night's homework answers.
19. a. 2264 J/g
b. 333.5 J/g
20. 84.3 J/g
21. a. 0.277 mol
b. 15.5 kJ/mol
22. a. 21.8 mol
b. 15.5 kJ/mol

NOTES

Charles Law (cont)
Charles Law: Volume-Temperature between volume and temperature was discovered by the French scientist Jacques Charles in 1787.
Charles found that the volume changes by 1/273 of the original volume for each Celsius degree, at a constant pressure and at an initial temperature of 0 degrees C.
The temperature 273 is absolute zero and is given a value of zero in the Kelvin temperature scale. The relationship between the two temperature scales is K=273.15 +degrees C.
Charles Law states that the volume of a fixed mass of gas at a constant pressure varies directly with the Kelvin temperature.
Gas volume and Kelvin temperature are directly proportional to each other at constant pressure.
Mathematically, Charles Law can be expressed as: V=KT or V/T=K where V is the volume, T is the Kelvin temperature, and K is a constant. the ratio V/T for any set of volume temperature values always equals the same K.
The equation reflects the fact that volume and temperature are directly proportional to each other at constant pressure.
The form of Charles Law that can be applied directly to most volume- temperature gas problems is: V1/T1 = V2/T2.
V1 and T1 represent initial conditions, and V2 and T2 represent another set of conditions.
Given three of the four values, V1, T1, V2, and T2, you can use this equation to calculate the 4th value for a system at constant pressure.
Gay-Lussacs Law: Pressure Temperature Relationship
At a constant volume, the pressure of a gas increases with increasing temperature.
Gas pressure is the result of collisions of molecules with container walls.
The energyu and frequency of collisions depend on the average kinetic energy of the molecues.
Pressure is directly proportional to Kelvin temperature.
Gay Lussacs Law: The pressure of a fixed mass of gas at constant volume varies directly with the Kelvin temperature.
This law is named after Joseph Gay-Lussac, who discovered it in 1802.
Mathematically, Gay Lussacs Law can be expressed as P=KT or P/T=K where P is pressure, T is the Kelvin temperaure, and K is a constant. The ratio P/T for any set of volume-temperature values always equals the same K.



Wednesday, February 17, 2010

2-17-10 THE 100TH BLOG OF THE YEAR!!!

This blog is a momentous occasion, for it is the 100th blog of our sophomore year of honor's chemistry. Instead of holding a fiesta at my house to celebrate this incredible event, I've gathered an extensive list of truly fascinating facts about the number 100:
  • On average, 100 people choke to death on ball-point pens every year (how sad).
  • Ben Franklin is on the face of the $100 bill.
  • In Greece, India and Israel, 100 is the police telephone number.
  • Nicodemus brought 100 pounds of myrrh & aloes to embalm Jesus after his crucifixion.
and here's the 100th blog.......

- To determine the pressure of a gas inside a collection bottle, you would use this equation, which is an instance of Dalton's Law of Partial Pressure:
- P(atmosphere) = P(gas) + P(water)

- If you raise the bottle until the water levels inside and outside the bottle are the same, the total pressure outside and inside will be the same.

- Reading the atmospheric pressure on a barometer and looking up the value of P(water) at the temperature of the experiment in a table (p. 859 in our book), you can calculate the P(gas).

Sample Problem B

- Oxygen gas from the decomposition of potassium chlorate, KClO3, was collected by water displacement. The barometric pressure and the temperature during the experiment were 731.0 torr and 20.0 degrees C respectively. What was the partial pressure of the oxygen collected?

G: Total Pressure = P(atmosphere) = 731.0 torr
P(water) = 17.5 torr (vapor pressure of water at 20.0 C from table A)
P(atmosphere) = P(oxygen) + P(water) ; solve for P(oxygen)
P(oxygen) = P(atm) - P(water)
substitute: P(oxygen) = 731.0 torr - 17.5 torr = 713.5 torr

- Boyle's Law
- Robert Boyle discovered that doubling the pressure on a sample of gas at constant temperature reduced its volume by 1/2
- explained by the Kinetic-Molecular Theory (Dr. B said to make sure and know this!)
- the pressure of a gas is caused by moving molecules hitting the container walls
- if the volume of the container is decreased, more collisions will occur and the pressure will increase
- if the volume of the container is increased, less collisions will occur and the pressure will decrease
- Boyle's Law states that the volume of a fixed mass of gas varies inversely with the pressure at constant temperature.
- Formula: PV=K (P=pressure, V=volume, K= constant)
-the inverse would be a straight line (V=K/P)
- Because of the transitive property of equality, since two different quantities are equal to the same thing (volume x pressure = K), it can be concluded that two separate sets of conditions are equal to each other (P1V1 = P2V2)

That's the blog, have a wonderful night.

Tuesday, February 16, 2010

blog by chris mathews

today we had chemistry class and i was assigned the blog...
we started chapter 11 YAY!!!

ch 11
the pressure formula is p=f/a such that p-pressure, f=force, and a is area
always remember that area is squared
the SI unit for area is N which means newton. it will increase the speed of one kilogram mass by one meter per second that that force is applied.
pressure is a force per unit area, therefore pressure of a 500 N on a floor with an Area of 325 cm^2 is:

500 n / 325 cm^2 = 1.5 N/Cm^2

*the greater the force -> greater pressure
*smaller the area-> greater pressure KNOW THOSE TWO THINGS
introduced by Evangelista Toricelli who was constantly picked on by his parents, the ultimate teaser being his girlish name....

water pumps can raise about 34 feet
thought that it must be dependent on weight and weight of air
reasoned that since mercury was 14 times less dense than water, it would be 1/14 of 34 feet
tested it and it in rose 30 in.
pressures can be also measured in units of atmospheres. Because the average pressure is 760 mm of Hg or one torr named after evangelista.
In pascals pressure is exerted by one N on one square meter

Daltons law
the measure of full pressure in a gas is the sum of the measure of partial pressures

AND THATS THE BLOG

Thursday, February 11, 2010

Thursday, February 11, 2010

Section 4

Phase Diagrams
  • A phase diagram is a graph of pressure versus temperature that shows the conditions under which the phases of a substance exists
  • The triple point of a substance indicates the temperature and pressure conditions at which the solid, liquid, and vapor of the substance can coexist at equilibrium
  • The critical point of a substance indicates the critical temperature and critical pressure
  • The critical temperature (t sub c) is the temperature above which the substance cannot exist in the liquid state
  • Above this temperature, water cannot be liquefied, no matter how much pressure is applied
  • The critical pressure( P sub c) is the lowest pressure at which the substance can exist as a liquid at the critical temperature

Section 5

Water

Structure of Water

  • Water molecules consist of two atoms of hydrogen and one atom of oxygen united by polar-covalent bonds
  • The molecules in solid or liquid water are linked by hydrogen bonding
  • The number of linked molecules decreases with increasing temperature
  • Ice consists of water molecules in the hexagonal arrangement
  • The hydrogen bonds between molecules of liquid water at 0 degrees C are fewer and more disordered than those between molecules of ice at the same temperature
  • Liquid water is denser than ice
  • As the temperature approaches the boiling point, groups of liquid water molecules absorb enough energy to break up into separate molecules

Physical Properties of Water

  • At room temperature pure liquid water is transparent, odorless, tasteless, and almost colorless
  • The molar enthalpy of fusion of ice relatively large compared with the molar enthalpy of fusion of other solids
  • Water expands in volume as it freezes, because its molecules form an open rigid structure
  • This lower density explains why ice floats in liquid water
  • Both the boiling point and molar enthalpy of vaporization of water are high compared with those of non polar substances of comparable molecular mass
  • The values are high because of the strong hydrogen bonding that must be overcome for boiling point to occur
  • Steam (vaporized water) stores a great deal of energy as heat

Which will burn you worsts

(triangle) H sub f = 6.009 KJ/mole

(triangle) H sub v= 40. 79 KJ/mole

Wednesday, February 10, 2010

February 9th, 2010

Covalent Molecular Crystals
- The crystals structure of a covalent molecular substance consists of covalently bonded molecules held togethor by intermolecular forces.
- If the molecules are nonpolar, there are only weak London dispersion forces between molecules.
- Covalent moleculer crystals have low melting points, are easliy vaporized, and are good insulators

Amorphous Solids
- Amorphous means "without shape" in Greek
- Unlike atoms that form crystals, the atoms that make up amorphous solids aren't arranged in a regular pattern

Changes of State and Equilibrium
- a phase is any part of a system with uniform compisition and properties.
- Condensation is the process by which a gas changes to a liquid
- a gas in contact with its liquid or solid phase is called a vapor
- Equilibrium is a dynamic condition in which two opposing changes occur at equal rates in a closed system


-Eventually in a closed system, the rate of condensation equals the rate of evaporation and a state of equilibrium is established.

p.s. I am sincerely sorry to post this blog one day late and I hope you forgive me
Vapor molecules in equilibrium with a liquid in a closed system exert a pressure proportional to the concentration of molecules in the vaporphase.

The pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature is called the EQUILIBRIUM VAPOR PRESSURE of the liquid.

The equilibrium vapor pressure increases with temperature

increasing the temperature of a liquid increases the average kinetic energy of the liquid's molecules

Because all liquids have characteristic forces of attraction between their particles, every liquid has a specific equilibrium vapor pressure at a given temperature

VOLATILE LIQUIDS are liquids that evaporate readily and have weak forces of attraction between particles

NONVOLATILE LIQUIDS have strong forces of attraction between their particles

BOILING is the conversion of liquid to vapor on the surface as well as within the liquid

BOILING POINT of a liquid is the temperature at which the equilibrium vapor pressure equals the atmospheric pressure

The lower atmospheric pressure is the lower boiling point is

At the boiling point all the energy absorbed is used to evaporate the liquid and temperature remains constant as long as atmospheric pressure does not change

Normal atmospheric pressure is boiling point of water

Energy must be added continuously to keep a liquid boiling. and the temperature will remain constant despite constant addition of energy

MOLAR ENTHALPY OF VAPORIZATION is the amount of energy as heat needed to vaporize one mole of liquid at the liquids boiling point at constant pressure

the stronger the attrction between particles the more energy needed to overcome it

liquid to solid is FREEZING

FREEZING POINT is the temperature at which the solid and liquid are at equilibrium at 1 atm pressure.. at freezing point particles of the liquid and solid have the same kinetic energy

melting is the reverse of freezing and occurrs at constant temperature

at equilibrium melting and freezing proceed at equal rates
at normal atmospheric pressure the temperature of a system containing ice and liquid water will remain at 0 degrees C as long as both ice and water are present (and you keep stirring)

at sufficiently low temperature and pressure liquid cannot exist so the substaance exits equilibrium as vapor instead of liquid

SUBLIMATION is the change of state from a solid directly to a gas

DEPOSITION is a change of state directly from a gas to a solid

Tuesday, February 9, 2010

whos the blogger

today we took notes and watched Dr. B's (cute grandson according to matt orians) play animal crossing. we talk about solids, liquids, and gases which can be found in Ch. 10 of your book

Sunday, February 7, 2010

Friday

Law of Diffusion

Low Rate of Diffusion
  • The rate of diffusion is millions of times slower in solids than in liquids

Crystalline Solids

  • Crystalline solids exist either as single crystals of as groups of crystals fused together
  • The total three-dimensional arrangement of particles in the crystal can be represented by a coordinate system called the lattice
  • The smallest portion of a crystal lattice that shows the 3-D pattern of the entire lattice is called unit cell

Unit Cell Types

  • simple cubic (4 atoms)
  • body-centered (5 atoms)
  • face-centered (14 atoms)

Crystalline Solids

  • A crystal and its unit cells can have anyone of seven types of symmetry

Binding Forces in Crystals

  • Crystal structures can also be described in terms of the types of particles in them and the types of chemical bonding between the particles

  1. Ionic Crystals - The ionic crystals structure consists of positive and negative ions arranged in a regular pattern
  • These crystals are hard and brittle, have high melting points, and are good insulators

2. Covalent network crystals - In covalent network crystals, each atom is covalently bonded its nearest neighboring atoms

  • The covalent bonding extends throughout a network that includes a very large number of atoms
  • The network solids are very hard and brittle, have high melting points, and are usually nonconductors or semiconductors

3. Metallic Crystals - The metallic crystal structure consists of metal cations surrounded by a sea of delocalized valence electrons

  • The electron come from the metal atoms and belong to crystal as whole
  • The freedom of these delocalized electron to more throughout the crystal explains the high electric conductivity of metal's

Wednesday, February 3, 2010

February 3, 2010

The Test
People who got less than a 75 on the last test will be able to retake the test sometime next week (either Monday, Wednesday, or Friday), using the book. Dr. B will put your score on this test on the website in addition your previous test, so that it averages out.

The Lab
For the lab tomorrow, you have to do the normal prelab stuff: title, purpose, materials, procedure, data tables, and prelab questions.
You must also draw a grid with all the anions and cations. The cations will occupy the header of the grid, while the anions will occupy the left side of the grid.
You will first drop a cation into each well in the column, followed by the correct anion. After you drop the anion, you will need to make the following observations:
- Color change
- Gas release
- Precipitate
- No reaction

Notes

Definite Melting Point
- Melting is the physical change of a solid to a liquid by the addition of energy as heat
- The temperature at which a solid becomes a liquid is its melting point
- At this temperature, the kinetic energies of the particles within the solid overcome the attractive forces holding them together
- Amorphous solids are sometimes classified as supercooled liquids which are substances that retain certain liquid properties even at temperatures at which they appear to be solid
- These properties exist because the particles in amorphous solids are arranged randomly
High Density and Incompressability
- In general, substances are most dense in the solid state
- The higher density results from the fact that the particles of a solid are more closely packed than those of a liquid or a gas
- For practical purposes, solids can be considered incompressable

Reagents for the Lab
- Sodium phosphate – sodium is soluble, phosphate is an anion
- Potassium hydroxide – potassium is soluble, hydroxide is an anion
- Sodium oxalate – sodium is soluble, oxalate is an anion
- Cobalt chloride – chloride is soluble, cobalt is a cation
- Strontium chloride – chloride is soluble, strontium is a cation
- Potassium iron hexacyanate – potassium is soluble, iron hexacyanate is an anion
- Sodium carbonate – sodium is soluble, carbonate is anion
- Silver nitrate – nitrate is soluble, silver is a cation
- Copper (II) sulfate – sulfate is soluble, copper (II) is a cation
- Nickel (II) chloride – chloride is soluble, nickel (II) is a cation
- Potassium iodide – potassium is soluble, iodide is an anion
- Lead (II) nitrate – nitrate is soluble, lead (II) is a cation
- Iron (III) nitrate – nitrate is soluble, iron (III) is a cation

Tuesday, February 2, 2010

section 2 & 3

Properties of Liquids and the kinetic- molecular theory cont.
  • the particles in a liquid are not bound together in fixed positions, instead they move about constantly
  • a fluid is a substance that can flow and therefore take the shape of it container

relitively high density

  • at normal atmospheric pressurre, most substances are hundreds of times denser in a liquid state than in a gaseos state

relative incompressiblity

  • liquids are much less compressible than gasses because liquid particles are more closely packed together

ability to diffuse

  • any liquid gradually diffuses throughout any other liquid in which in can dissolve
  • the constant, random motion of particles causes diffusion in liquids

diffusion is much slower in liquids than in gasses

  • liquid particles are closer together
  • the attractive forces between the particles of a liquid slow their movement
  • as the temperature of liquid is increased diffusion occurs more rapidly

surface tension

  • a property common to all liquids is surface tension, a force that tends to pull adjacent parts of a liquid's surface together, thereby decreasing surface area to the smallest possible size
  • the higher the force of attraction between the particles of a liquid, the higher the surface tension
  • the molecules at the surface of the water can form hydrogen bonds with the water, but not with the molecules in the air above them
  • capillary action is the attraction of the surface of a liquid to the surface of a solid
  • this attraction tends to pull the liquid molecules upward along the surface and against the pull of gravity
  • the same process is responsible for the concave liquid surface, called a meniscus, that forms in a test tube or graded cylinder

evaporation and boiling

  • the process by which a liquid or solid changes to a gas is vaporization
  • evaporation is the process by which particles escape from the surface of a non-boiling liquid and enter a gas state
  • boiling is the change of a liquid to bubbles of vapor that appear throughout the liquid
  • evaporation occurs because the particles of a liquid have different kinetic energies

formation of solids

  • when a liquid is cooled, the average energy of its particles decrease
  • the physical changes of a liquid to a solid by removal energy as heat is called freezing or solidification

Section 3

  • The particles of a solid are more closely packed than those of a liquid or gas
  • All interparticle attractions exert stronger affects in solids than in the corresponding liquid or gasses
  • attractive forces tend to hold the particles of a solid in relatively fixed positions
  • solids are more ordered than liquids and much more ordered than gases
  • there are 2 types of solids, crystalline and amorphous solids
  • most solids are crystalline solids - they consists of crystals
  • a crystal is a substance in which the particles are arranged in an orderly, geometric, repeating pattern
  • an amorphous solid is one in which the particles are arranged randomly

Definite shape and volume

  • solids can maintain a definite shape without a container
  • crystalline solids are geometrically regular
  • the volume of a solid changes only slightly with a change in temperature or pressure
  • solids have definite volume because their particles are packed closely together

Monday, February 1, 2010

Monday, February 1, 2010

Chapter 10 Section 1

The Kinetic-Molecular Theory of Matter
  • The Kinetic-Molecular Theory is based on the idea that particles of matter are always in motion
  • The theory can be used to explain the properties of solids, liquids, and gases in terms of particles and the forces that act between them

The Kinetic-Molecular Theory of Gas

  • An ideal gas is a hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory
  • The kinetic-molecular theory of gases is based on the following five assumptions:

1. Gases consists of large number's of tiny particles that are far apart relative to their size

  • Most of the volume occupied by a gas is empty space

2. Collisions between gas particles and between particles and conatiner walls are elastic collisions

  • An elastic collision is one inwhich there is no net loss of total kinetic energy

3. Gas particles are in continuous, rapid, random motion. They therefore possess kinetic energy which is energy of motion

4. There are no forces of attraction between gas particles

5. The temperature of a gas depends on the average kinetic energy of the particles of the gas

  • The kinetic energy of any moving object is given by this equation: KE= (1/2)(m)(v)^2
  • V- velocity M-kilograms K-Kinetic Energy Answer is in Joules(J)

The Kinetic Molecular Theory of Gas(continued)

  • All gases at the same temperature have the same average kinetic energy
  • At the same temperature, lighter gas particles, have higher average speeds than do heavier gas particles
  • Hydrogen molecules will have a higher speed than oxygen molecules

The Kinetic-Molecular Theory and the Nature of Gases

  • The Kinetic-Molecular Theory applies only to ideal gases
  • Many gases behave nearly ideally if pressure isn't very high and temperature isn't very low

Expansion

  • Gases don't have a definite shape or a definite volume
  • The completely fill any container in which they are encolsed
  • Gas particles move rapidly in all directions (assumption 3) without significant attractino between them (asumption 4)

Fluidity

  • Because the attraction forces betwen gas particles are insignificant (assumption 4) gas particles glide easily past one another
  • Because liquids and gases flow, theyre both referred to as fluids

Low Density

  • THe density of a gaseous substance at atmosphere pressure is about 1/1000 the density of the same substance in the liquid or solid state
  • The reason is that the particles are so much farther apart in the gaseous state (assumption 1)

Compressibility

  • During compression, the gas particles, which are initially very far apart (assumption 1) are crowded close together

Diffusion and Effusion

  • Gases spread out and mix with one another, even without being stirred
  • The random and continuous motion of the gas molecules (assumption 3) carries them throughout the available space
  • Such spontaneous mixing of the particles of two substances by their motion is called diffusion
  • Effusion is a process by which gas particles pass through a tiny opening
  • The rates of effusion of different gases are directly proportionally to the velocities of their particles
  • Molecules of low mass effuse faster than molecules of high mass

Deviations of Real Gases from Ideal Behavior

  • Because particles of gases occupy space and next attractive forces on each other, all real gases deviate to some degree from ideal gas behavior
  • A real gas is a gas that doesn't behave completely according to the assumptions of the kinetic-molecular theory
  • At very high pressures and low tempreratures a gas is most likely to behave like a non-ideal gas
  • The more polar the molecules if a gas are, the more the gas will deviate from ideal gas behavior

Chapter 10 Section 2

Liquids

Properties of Liquids Kinetic-Molecular Theory

  • A liquid can be descried as a form of matter that has a definite volume and takes the shape of its container
  • The atractive forces between particels in a liquid are more efective than those between particles in a gas
  • This attraction between liquid particles is caused by the intermolecular forces
  • Dipole-Dipole forces
  • London dispersion forces
  • Hydrogen Bonding