Temperature and Kinetic Theory
-
Upload
macayle-faughnan -
Category
Documents
-
view
41 -
download
2
description
Transcript of Temperature and Kinetic Theory
![Page 1: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/1.jpg)
Temperature and Kinetic Theory
Chapter 13
1
![Page 2: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/2.jpg)
Atoms and Molecules
2
Atomic theory says that matter is made of atoms; Greek for indivisible
To discuss the relative mass of atoms and molecules we need a unit
This unit is called unified atomic mass units (u) or atomic mass unit (amu)
Based on carbon-12
![Page 3: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/3.jpg)
Atomic Theory of Matter On a microscopic scale, the arrangements of
molecules in solids (a), liquids (b), and gases (c) are quite different.
3
![Page 4: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/4.jpg)
Kinetic-molecular theory Explains the properties of an ideal gas
Says that particles in a gas are in random motion at high speeds
Gas particles undergo perfectly elastic collisions
Gas particles hit each other and/or container and rebound, resulting in pressure on the surface
Theory explains the properties of an ideal gas, which is an accurate model of real gases under most conditions
4
![Page 5: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/5.jpg)
Temperature Temperature is a measure of how hot
or cold something is.
The average translational kinetic energy of the molecules in an ideal gas is directly proportional to the temperature of the gas.
Most materials expand when heated.
5
![Page 6: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/6.jpg)
Thermal Equilibrium and the Zeroth Law of Thermodynamics
Two objects placed in thermal contact will eventually come to the same temperature. When they do, we say they are in thermal equilibrium.
The zeroth law of thermodynamics says that if two objects are each in equilibrium with a third object, they are also in thermal equilibrium with each other.
![Page 7: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/7.jpg)
Temperature
7
In everyday life temperature might be measured in Fahrenheit or Celsius
To convert between F and C 7F= 9/5 7C + 32
The SI unit of temperature is kelvin (K)
To convert between K and C K= 7C + 273.15
![Page 8: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/8.jpg)
The Gas Laws
Boyle’s Law - for a fixed sample of gas at constant temperature, the volume of the gas varies inversely w/ the pressure.
P1V1=P2V2
8
![Page 9: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/9.jpg)
Charles’s Law – under constant pressure, the volume of a sample of gas varies directly with its Kelvin temperature
Guy-Lussac’s Law-at constant volume the absolute pressure of a gas is directly proportional to the absolute temperature
9
![Page 10: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/10.jpg)
We can combine these…
Combined Gas Law – for a fixed amount of an ideal gas, the pressure times the volume divided by the Kelvin temperature equals a constant
10
![Page 11: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/11.jpg)
Moles A mole (mol) is defined as the number of
grams of a substance that is numerically equal to the molecular mass of the substance:
1 mol H2 has a mass of 2 g
1 mol Ne has a mass of 20 g
1 mol CO2 has a mass of 44 g
The number of moles in a certain mass of material:
![Page 12: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/12.jpg)
Molecules & Avogadro’s Number The number of molecules in one mole
is the same for all gases. That number is Avogadro’s number
![Page 13: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/13.jpg)
The Ideal Gas Law
Where n is the number of moles R is the universal gas constant has a
value of 8.314 J/mol·K. In the real world, this ideal gas law
predicts gas behavior well, except under conditions of high pressure or low temperature
![Page 14: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/14.jpg)
.Real gases and Changes of Phase A phase (PT) diagram shows all three phases
of matter • Solid-liquid transition is melting or freezing
• Liquid-vapor transition is boiling or condensing
• Solid-vapor transition is sublimation
![Page 15: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/15.jpg)
Phase diagram of carbon dioxide
The triple point is the only point where all three phases can coexist in equilibrium.
![Page 16: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/16.jpg)
Diffusion Even without stirring, a few drops of
dye in water will gradually spread throughout. This process is called diffusion.
![Page 17: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/17.jpg)
. Diffusion occurs from a region of high
concentration towards a region of lower concentration
![Page 18: Temperature and Kinetic Theory](https://reader031.fdocuments.net/reader031/viewer/2022020718/5681309f550346895d969707/html5/thumbnails/18.jpg)
References
18
Zitewitz. Physics: Principles and Problems. 2004
Giancoli, Douglas. Physics: Principles with Applications 6th Edition. 2009.
Images http://
missbakersbiologyclasswiki.wikispaces.com/file/view/diffusion.gif/31772061/diffusion.gif