States+of+Matter+and+The+Behavior+of+Gases

=__Chapters 13 and 14: States of Matter and The Behavior of Gases__ =

By Period D
This wiki page outlines chapters 13 (States of Matter) and 14 (The Behavior of Gases) from Prentice Hall's __Chemistry__. Chapter 13 describes characteristics of gases, liquids, and solids. It also goes into sublimation and how substances change state. Some key terms to know are kinetic energy, kinetic theory, gas pressure, vacuum, atmospheric pressure, barometer, pascal, standard atmosphere, vaporization, evaporation, vapor pressure, boiling point, normal boiling point, melting point, crystal, unit cell, allotropes, amorphous solid, glass, sublimation, phase diagram, and triple point. These terms will be described in the sections below. Chapter 14 focuses on the behavior of gases. Key terms include compressibility, ideal gas constant, partial pressure, diffusion, and effusion. This chapter also includes some laws pertaining to gases like Boyle's law, Charles's law, Gay-Lussac's law, combined gas law, ideal gas law, Dalton's law of partial pressure, and Graham's law of effusion. These too will be explained in the following sections.



[|Book site with practice quizzes and relevant links]

media type="youtube" key="ORI8PrcrLVs?version=3" height="273" width="448" align="center"

Sublimation Explanation media type="youtube" key="YNSpwidaxMg?version=3" height="273" width="448" align="center"

Ideal Gas Law Practice

Powerpoint by me explaining 6 of the Gas Laws

Editor: Lauren Sachs

**Group 1: Nature of Gases** **Group 2: Nature of Liquids** **Group 3: Nature of Solids** **Group 4: Properties of Gases** **Group 5: The Gas Laws** **Group 6: Ideal Gases** **Group 7: Mixtures and Movements**
 * Co-editor: Zach Boulerice (Pgs. 385-386)*
 * Alex Trombetta (Pgs. 387-389)
 * Co-editor: Sahana Nazeer (Pgs. 390-393)
 * Ian Travis (Pgs. 394-395)
 * Co-editor: Joe Hatch (Pgs. 396-399)
 * Kevin McAllister (Pgs. 400-403)
 * Co-editor: Andrew Ware (Pgs. 416-417)
 * Henry Dodge (Pgs. 413-415)
 * Co-editor: Jess Mahoney (Pgs. 418-421)
 * Nick Romero (Pgs. 422-425)
 * Co-editor: Cassie Naimie (Pgs. 428-429)
 * Chris Hughes (Pg. 426)*
 * Erin Cropanese (Pg. 427)
 * Co-editor: Gabe Hannawi (Pg. 437)
 * Tess Murphy (Pgs. 432-434)
 * Caity Vogt (Pgs. 435-436)

=__ Chapter 13 __=

**Kinetic Theory and a Model for Gases**
By Lauren Sachs media type="youtube" key="8jelON52wMw?version=3" height="351" width="576" align="center"
 * **Kinetic Energy**: the energy an object has because of its motion
 * **Kinetic Theory**: All matter consists of tiny particles that are in constant motion
 * The particles of a gas are considered to be hard spheres with an insignificant volume
 * The motion of the particles in a gas is rapid, constant, and random
 * All collisions between particles in a gas are perfectly elastic

Gas Pressure
By Alex Trombetta The SI Unit for pressure is the pascal which can be abbreviated to (Pa). A pascal is a very small amount of pressure in the fact that the normal atmospheric pressure is 100,000 pascals. Pressure can also be measured using millimeters of mercury and atmospheres. Millimeters of mercury can be abbreviated to (mm Hg), and atmospheres can be abbreviated to (atm). 1 standard atmosphere is equal to the pressure required to support 760 mm Hg in a mercury barometer at 25 degrees. (mm Hg)=(torr) so therefore 1 atm=760torr=101.3kPa ^note that 1kPa=1000Pa Ex: Convert 234 atm to torr. conversion factor 1 atm =760 torr. 234 atm= x torr 234 atm x 760 torr = 177840 torr
 * __Conversion Problems__**

Ex: Convert 249300 kPa to atm conversion factor 101.3 kPa= 1 atm 249300 kPa = x atm __249300 kPa__ = 2461.01 atm 101.3kPa

__**Practice Problems**__ media type="youtube" key="qv81QCGNnVo?version=3" height="390" width="640"
 * 1.) Convert 23 atm to torr**
 * 2.) Convert 10273 kPa to atm**
 * 3.) Convert 41.29 torr to Pa**

**Kinetic Energy and Temperature** By Alex Trombetta --->Key Concept: The Kelvin temperature of a substance is directly proportional to the average kinetic energy of the particles of the substance.

When particles is stored in a substance, this energy is called potential energy. Energy can be stored in an object by heating it. The potential energy does not raise the temperature, but it does speed up the particles and therefore increases there kinetic energy. This increase in kinetic energy is the cause for the temperature increase. __Average Kinetic Energy__ At a certain temperature particles can have many kinetic energy levels. Usually, particles have kinetic energies somewhere in the middle. We calculate the average kinetic energy instead. Therefore, in a substance, all of the particles share the same amount of average kinetic energy as all of the other particles in that same substance. Substances in different physical states can still share the same average kinetic energy. The kinetic energy of the particles in a substance and the substances temperature share a direct relationship. For example, if one is to raise the temperature of a substance, then the amount of kinetic energy will also increase. Same concept with cooling in the fact that the colder the substance the less kinetic energy. When particles are not moving and have not kinetic energy, they have reached Absolute zero. Absolute zero is equal to 0 Kelvin, or -213.15 degrees C. This temperature has never been reached but we have come very close. __Average Kinetic Energy and Kelvin Temperature__ Kelvin scale directly reflects the relationship between average kinetic energy, and temperature. In fact, the average kinetic energy is proportional to the temperature at K. Therefore, the particles in the gas of O at 50K has 5 times the amount of kinetic energy as that of the gas of O at 10K.

A Model for Liquids
By Sahana Nazeer Both particles in gases and liquids have kinectic energy, which allows those particles to flow past one another. - substances that flow are referred to as fluids - the ability of gases and liquids to flow allows them to take the shape of their container The main difference between gases and liquids is that //in a gas, there are no attractions between the particles// unlike //the particles in a liquid that are attracted to each other.// //-// this particle attraction in liquids allows for liquids to have volume, while gases do not. - increasing pressure on a liquid hardly affects the volume of the liquid -- the same can be accurately stated for solids, hence liquids and solids can be referred to as **//condensed states of matter//**
 * The interplay between the disruptive motions of particles in a liquid and the attractions among the particles determines the physical properties of liquids.**
 * -** reduces the amount of space between particles in a liquid, hence liquids are more dense than gases but less dense than solids

Evaporation
By Sahana Nazeer - during this process, only those molecules with a certain minimum kinetic energy can escape from the surface of the liquid - liquids evaporate faster when heated because the average kinetic energy of its particles are increased (allows them to overcome the attractive forces keeping them in the liquid state) When evaporation occurs, the particles with the highest kinetic energy escape first and the particles that have the lower average kinetic energy are left in the liquid. Evaporation is a **cooling** process because the liquid's temperature decreases as evaporation occurs. - perspiration is an example of evaporation and its cooling effects
 * The conversion of a liquid to a gas or vapor is called __vaporization__**//.// //When this conversion occurs at the surface of a liquid that is not boiling, it is called **__evaporation__**//.
 * The evaporation of a liquid in a closed container is different from evaporation in an open container.**

Vapor Pressure
By Sahana Nazeer //Vapor pressure is a measure of the force exerted by a gas above a liquid.// //-// when a liquid evaporates, it becomes a vapor (gas) - when a vapor (gas) goes through condensation, it becomes a liquid - particles that once evaporated are condensing, but other particles are evaporating to take their place
 * In a system at constant vapor pressure, a dynamic equilibrium exists between the vapor and the liquid. The system is in equilibrium because the rate of evaporation of liquid equals the rate of condensation of vapor.**
 * -** in equilibrium, the particles in the system continue to evaporate and condense, but there is no net change in the number of particles in the liquid or vapor

- vapor pressure of a liquid indicates how volatile the substance is, referring to how easily it evaporates
 * An increase in the temperature of a //contained// liquid increases vapor pressure** because the particles in the warmer liquid have increased kinetic energy.


 * Manometers are used to determine the vapor pressure of a liquid.**

Boiling Point
By Ian Travis - bubbles of vapor forming throughout the liquid typically characterize the liquid boiling
 * When a liquid is heated to a temperature at which particles throughout the liquid have enough kinectic energy to vaporize, the liquid begins to boil.**
 * -** the temperature at which the vapor pressure of the liquid is just equal to the external pressure on the liquid is the __boiling point **(bp)**__

- atmospheric pressure is lower at higher altitudes, therefore **boiling points decrease at higher altitudes** -during boiling, while the liquid is at its boiling point, particles with the highest kinetic energy escape first (like evaporation) -the vapor produced is at the same temperature of the boiling liquid, and it may have the same average kinectic energy as the liquid, but **//the vapor has more potential energy//** //The normal boiling point is the boiling point of a liquid at a pressure of 101.3kPa, or 1 atm because a liquid can have various boiling points based on its variations in pressure.// Here is a video quiz that includes all the information explained in this section of chapters 13&14: media type="youtube" key="oDtzICqlcwE" height="349" width="425" Video By: Sahana Nazeer
 * The boiling point varies with altitude, even with the same liquid** because a liquid only boils when the vapor pressure of particles within the liquid equals the atmospheric pressure.
 * - at a lower external pressure**, the particles in the liquid need less kinetic energy to escape from the liquid, hence the **boiling point decreases**
 * __Boiling is a cooling process__,** similar to evaporation.
 * -the temperature of a boiling liquid never rises above its boiling point, the liquid only boils faster**

13-3: The Nature of Solids
By: Joe Hatch (co-editor)

A Model for Solids [[image:http://image.tutorvista.com/content/matter/solid-particles.jpeg width="186" height="149" align="right"]]

 * -atoms are tightly packed together
 * -dense, not easy to compress
 * -do not flow, unlike liquids and gases
 * -**__melting point__**- temperature at which a solid changes into a liquid
 * -this happens because the vibrations of the particles become strong enough to overcome the attractions they have between each other
 * melting point = freezing point

Crystal Structure and Unit Cells

 * -most solids are **crystalline**
 * -**__crystal__**- particles are arranged in an orderly, repeating, three-dimensional pattern
 * -this pattern is called a crystal lattice
 * -ionic solids have high melting points and molecular solids have relatively low melting points
 * -the difference is due to the strength of the forces that hold them together

Crystal Systems

 * -sides of a crystal are called **faces**
 * -the angles of which the faces of the crystals intersect are unique and can identify the substance
 * -crystals are separated into 7 different groups: cubic, tetreagonal, orthorhombic, monoclinic, triclinic,hexagonal,and rhombohedral
 * -the particles within the crystal determine it's shape
 * -**__unit cell__-** the smallest group pf particles within a crystal that retains the geometric shape of the crystal

Allotropes

 * -**__Allotropes__**- two or more different molecular forms of the same element in the same physical state
 * -the elements that form allotropes are: carbon, phosphorus, sulfur, oxygen, boron, antimony

Non-Crystalline Solids [[image:http://www.hcc.mnscu.edu/chem/V.17/amorphous_solid.jpg width="244" height="119" align="right"]]

 * -**__amorphous solid__**- a solid that lacks an ordered internal structure
 * -ex. Rubber, plastic, glass
 * -**__glass__**- a transparent fusion product of inorganic substances that have cooled to a rigid state without crystallizing
 * -glass does not melt, but bends at different temperatures

**13-4: Changes of State** By: Kevin McAllister


 * Ice Changes directly into water vapor without passing through a liquid state
 * This occurs because solids like liquids, have a vapor pressure and sometimes those pressures exceed the atmospheric pressure
 * Examples of Sublimation include Iodine and Dry Ice
 * Sublimation is used by Organic chemists to separate mixtures and to purify compounds
 * [|This Video] on the Sublimation of Iodine demonstrates the solid to gas energy transfer

**Phase Diagrams:**
 * A **phase diagram** is something that gives conditions of temperature and pressure at which a substance exists as a a solid a liquid or a gas
 * It's like a cheat sheet of when different substances are the different phases
 * The conditions of pressure and temperature at which two phases exist in equilibrium are indicated on a phase diagram by a line separating the phases
 * This line separates the phases from one another
 * A **Triple Point** is the point on a phase diagram which describes the conditions needed for all three phases to exist with one another.
 * Points above and below the triple point show the different phases that the substance can be
 * For Water, the triple point is at .016 degrees Celsius and .61 kPA for pressure
 * [|This Website] will help you more with Phase diagrams

=__ Chapter 14 __=

Compressibility
By Henry Dodge - Similar to the way a gas expands to fill its container, gases can also be compressed easily. - **Compressibility** is a measure of how much the volume of matter decreases under pressure - **Gases are easily compressed because of the space between the particles in a gas.** - The distance between particles of a gas is much greater than that of a solid or liquid.



Factors Affecting Gas Pressure
By Henry Dodge - particles in a gas move freely and randomly because there are no significant forces of attraction or repulsion among particles. - 4 variables used to describe a gas: pressure (P) in kilopascals, volume (V) in liters, temperature (T) In Kelvins, and the number of moles (n). - **the amount of gas, volume, and temperature are factors that affect gas pressure.** - Adding gas to a container increases the number of particles, which increases the number of collisions, which explains why the gas pressure increases. - Excessive pressure can cause a containers to swell or burst.

====Volume ==== By Andrew Ware - You can raise the pressure exerted by a contained gas by reducing its volume.

- The more the gas is compressed the greater the pressure within the container is.

Temperature
By Andrew Ware - An increase of temperature in an enclosed gas causes an increase in its pressure. - As a gas is heated, the temperature increases and the average kinetic energy of the particles in the gas increase.



Boyle's Law: Pressure and Volume
By Jess Mahoney
 * **If the temperature is constant, as the presure of a gas inceases, the volume decreases.**
 * **In turn, at the pressure decreases, volume increases.**
 * __Robert Boyle__ was the first to study this relationship using a systematic method.
 * For a given mass at constand temperature, the volume varies inversely with pressure.
 * //Sample Problem:// A balloon contains 30.0 L of helium gas at 103 kPa. What is the volume of hte helium when the balloon rises to an altitude where the pressure is only 25.0 kPa? (Assume the temperature remains constant.)
 * Knowns: P1= 103 kPa, V1= 30.0L, P2=25.0 kPa
 * Unknown: V2= ? L
 * Use Boyle's Law (P1V1 = P2V2)
 * Rearrage the law to isolate V2: V2= V1 x P1 / P2. V2= 30.0L x 103 kPa/ 25.0 kPa = 1.24 x 10^2 L

** Charles's Law: Temperature and Volume **
By Jess Mahoney
 * **As the temperature of an enclosed gas increases, the volume increases, if the pressure is constant.**
 * **(the volume of a fixed gas mass is directly proportional to its Kelvin temperature if pressure is constant.)**
 * 1787- French physicist Jaques Charles studied the effect of temperature on the volume of a gas at constant pressure
 * //Sample Problem:// A balloon inflated in a room at 24 *C has a volume of 4.00 L. The balloon is then heated to a temperature of 58*C. What is the new volume if the pressure remains constant?
 * Knowns: V1= 4.00 L, T1= 24 *C, T2= 58 *C
 * Unknown: V2= ? L
 * Use Charles's law (V1/T1= V2/T2)
 * T1= 24 *C + 273= 297 K ( You're using a gas law so you have to use Kelvins)
 * Rearrrange the law to isolate V2= Tv x T2/ T1
 * V2= 4.00 L x 331 K/ 297 K = 4.46 L

Gay-Lussac's Law: Pressure and Temperature
By Nick Romero media type="youtube" key="f9vnvFka8zw" height="349" width="425"

**The ratio between the volumes of the reactant gases and the products can be expressed in simple whole numbers.**

where: **//P//** i**s the [|pressure] of the gas.****//T// is the [|temperature] of the gas (measured in Kelvin).****//k// is a [|constant] .**

**The Combined Gas Law** By Nick Romero The **combined gas law** is a [|gas law] which combines [|Charles's law], [|Boyle's law] , and [|Gay-Lussac's law].

<span style="line-height: 1.5em; margin-bottom: 0.5em; margin-left: 0px; margin-right: 0px; margin-top: 0.4em;">This can be stated mathematically as <span style="line-height: 1.5em; margin-bottom: 0.5em; margin-left: 0px; margin-right: 0px; margin-top: 0.4em;">where: //p// is the <span style="background-attachment: initial; background-clip: initial; background-color: initial; background-image: none; background-origin: initial; background-position: initial initial; background-repeat: initial initial; color: #0645ad; text-decoration: none;">[|pressure] //V// is the <span style="background-attachment: initial; background-clip: initial; background-color: initial; background-image: none; background-origin: initial; background-position: initial initial; background-repeat: initial initial; color: #0645ad; text-decoration: none;">[|volume] //T// is the <span style="background-attachment: initial; background-clip: initial; background-color: initial; background-image: none; background-origin: initial; background-position: initial initial; background-repeat: initial initial; color: #0645ad; text-decoration: none;">[|temperature] measured in <span style="background-attachment: initial; background-clip: initial; background-color: initial; background-image: none; background-origin: initial; background-position: initial initial; background-repeat: initial initial; color: #0645ad; text-decoration: none;">[|kelvins] //k// is a constant (with units of energy divided by temperature). <span style="line-height: 1.5em; margin-bottom: 0.5em; margin-left: 0px; margin-right: 0px; margin-top: 0.4em;">For comparing the same substance under two different sets of conditions, the law can be written as:

media type="youtube" key="TJn0zaHnP4k" height="349" width="425"

Ideal Gas Laws
By Lauren Sachs
 * To calculate the number of moles of a contained gas requires an expression that contains the variable n
 * **Ideal gas constant (R)**: has the value of 8.31 (L*kPa)/(K*mol)
 * **Ideal gas constant**: The law that contains all 4 variables (P,V,T, and n) and is often written as P x V=n x R x T
 * <span style="background-attachment: initial; background-clip: initial; background-color: initial; background-origin: initial; background-position: 100% 50%; background-repeat: no-repeat no-repeat; cursor: pointer; padding-right: 10px;">[|ideal gas law site] **

**Sample Problem** By Erin Cropanese

1. List the knowns and unknown. (the chart that Mr. D says is helpful so that you don't have to look back at the actual problem) 2. Calculate the number of moles using the ideal gas law as shown above. Use the molar mass to convert moles to grams then convert grams to kilograms.
 * Problem**: A deep underground cavern contains 2.24X10^6 L of methane gas (CH4) at a pressure of 1.50 X10^3 kPa and a temperature of 315 K. How many kilograms of CH4 does the cavern contain?
 * P= 1.50 x10^3 kPA
 * V= 2.24 x10^6 L
 * T= 315 K
 * R= 8.31 (LxkPA)/(Kxmol)
 * *UNKOWN->? kg CH4

Rearrange the equation to solve for //n.// //n//= __PxV__ RxT Substitute the known quantities into the equation.

//n =// __(1.50 x 10^3 kPa0 x (2.24 x 10^6 L)__ = 1.28 x 10^6 g CH4 8.31 mol x 3.15 K =2.05 x 10^7 g CH4

Convert to kilograms---> 2.05 x10^7 g CH4 x __1 kg__ = 2.05 x 10^4 kg CH4 10^3 g 3. Evaluate. Although methane is compressed, its volume is ery large. So it is reasonable that the cavern contains a large mass of methane.

For more problems and steps go to the website below. []

Ideal Gas Laws and Real Gases
By Cassie Naimie

An //ideal gas// follows the gas laws at all conditions of pressure and temperature including assumptions of kinetic theory.
The particles in an "ideal gas" can have no volume or attraction between particles. Therefore, an "ideal gas" does NOT exist. Yet, some real gases at certain conditions can behave the same way as an ideal gas. In a real gas, there is both volume and attraction amongst particles. A real gas can condense and solidify when compressed and cooled. If water vapor is cooled below 100degrees Celsius standard atmospheric pressure, it becomes a liquid. Different conditions are required for different gases to solidify and condense. __REAL GASES DEVIATE FROM THE IDEAL__
 * Real gases are most different from ideal gases at low temperatures and high pressures.**

This diagram shows how the value of the ratio changes as pressure increases. For an "ideal gas" the result is the horizontal line because the ratio is always equal to 1. For real gases at high pressure, the ratio deviates from the ideal. These deviations are caused by 2 factors: the attractive force reduces the distance between particles and the gas occupies less volume causing the ratio to be less than 1 or the actual volume of the molecules causes the ratio to be greater than 1.

Dalton's Law
Tess Murphy Pages 432- 434
 * Gas pressure is caused by particles in a gas colliding with an object
 * The more particles in a given volume, the more collisions that will occur
 * The more average kinetic energy, the more collisions that will occur
 * In both above cases, pressure increases
 * When particles in a mixture of gases have the same temperature, they have the same average kinetic energy
 * Dry air- air that does not contain any water vapor
 * Partial pressure- contribution each gas in a mixture makes to the total pressure
 * The sum of the partial pressures= total pressure
 * Dalton’s Law of Partial Pressure- at the same volume and temperature, the total pressure of a mixture of gases equals the sum of the partial pressures of the gases that make it up
 * The fraction of the pressure exerted by a gas doesn’t change when the total pressure changes as long as the percent composition of a mixture of gases does not change



Composition of Dry Air media type="youtube" key="tTGehRESHmA" height="349" width="560" [|Dalton's Law Practice Problems!]
 * **Component** || **Volume(%)** || **Partial Pressure (kPA)** ||
 * Nitrogen || 78.08 || 79.11 ||
 * Oxygen || 20.95 || 21.22 ||
 * Carbon Dioxide || 0.04 || 0.04 ||
 * Argon and others || 0.93 || 0.95 ||
 * Total || 100.00 || 101.32 ||

Graham's Law
Caitlyn Vogt Page 435-436 Diffusion- the tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout *remember gas is never still; it is always in motion Ex: So say that there was this nasty container of broccoli that has been sitting in “Fred’s “fridge for a month. Finally, when he decides that he needs the container to reuse, Fred might open the container of broccoli and wash the container out. When Fred opens the lid of the container the gas particles that have been living inside the container will go into the air already existing and try to make the concentration in the air even in all areas of Fred’s apartment, thus resulting in the smell engulfing the living quarters ultimately putting his pet hamster Rufus into a state of shock. IE DIFFUSION Effusion- gas escapes through a tiny hole in its container Ex: in reference to the previous example, the only difference would be that Fred randomly decided to poke a hole in his reusable container and that is the passageway in which the nasty air molecules left the broccoli container to enter the air. The air molecules still escaped from the container and moved around the room and still shocked the hamster Rufus with odor. If you don’t understand the previous example, look at this video below as another example of effusion: <span style="background-clip: initial; background-origin: initial; background-position: 100% 50%; cursor: pointer; margin: 0px 0px 0in; padding-bottom: 0px; padding-left: 0px; padding-right: 10px; padding-top: 0px;">[] the only real point of this was to show that the axe left from one hole in the can… __**BIG RULE: Gases of lower molar mass diffuse and effuse faster than gases of higher molar mass**__ Thomas Grahm A Scottish chemist named Thomas Graham found that the rate of effusion of a gas is inversely proportional to the square root of the gas’s molar mass Its also applies to the diffusion of gases This video really helped me understand the concept: Check it Out if You’re struggling! (it includes sample problems and the thinking process when solving) <span style="background-clip: initial; background-origin: initial; background-position: 100% 50%; cursor: pointer; margin: 0px 0px 0in; padding-bottom: 0px; padding-left: 0px; padding-right: 10px; padding-top: 0px;">[]

Gabriel Hannawi
Pg. 437

Effusion: The process that occurs when a gas escapes through a tiny hole in its container. __Rate A__ = <span style="font-family: &#39;Times New Roman&#39;,serif; font-size: 14px; margin-bottom: 0pt; margin-left: 0in; margin-right: 0in; margin-top: 0in;">__√____ molar mass B __ Rate B <span style="font-family: &#39;Times New Roman&#39;,serif;">√ <span style="display: inline !important; margin-bottom: 0in; text-decoration: overline;">molar mass A