KEY: the balls are moving at DIFFERENT speeds CHAPTER 13 GASES (Temperature) Date _____________ TEMPERATURE (what the heck the heck is it?) Temperature is a measure of _________________________________ which is: _____________________________________________ _____________________________________________________ motion of the RP’s is: 1. ______________________ 2. ______________________ pool table analogy – elastic vs inelastic collisions – the total KE of all the RP of a sample energy of motion random (all directions) at different speeds (centered on an average) start with all at rest KEY: the balls are moving at DIFFERENT speeds strike cue ball (luckily) and hit the front ball of the pack all the balls start to move about / colliding with each other and the walls of the pool table eventually, the pool balls come to a stop the KE of the pool balls is transformed into thermal energy inelastic collisions (KE is not conserved) KEY particles as small as RP collide elastically elastic collisions – KE is conserved the particles have the same speed before and after the collision OR if one slows down, one must speed up

#RP speed (m/s) Distribution of pool table balls with respect to speed 10 20 30 40 50 1 3 4 5 6 2 0-10 10-20 20-30 30-40 40-50

Distribution of RP with respect to speed / KE in a sample average 300,000,000 m/s the fastest anything can go is the speed of light (c)…. maybe #RP few here really, really slow really, really fast speed (m/s) few here Maxwell-Boltzmann distribution the slowest anything can go is “stopped” #RP area under the curve = total # RP speed (m/s)

KE = ½ × mv2 how does temperature relate to ? Distribution of RP with respect to speed / KE in a sample Maxwell-Boltzmann distribution KE = ½ × mv2 #RP speed (m/s) area under the curve = total #RP how does temperature relate to ? at 273 K (OC)

Temperature and Maxwell-Boltzmann Distribution for a given sample (a collection of billions of billions of RP) “hotter” = _______________________________ know … Temperature – increases OR decreases OR stays the same Kinetic Energy of the RP – increases OR decreases OR stays the same or on average, the RP _______________________________ or, more ________________________________ and fewer _______________________ still same limits _________ and ____________ thermal energy increases move faster KEavg KEavg move faster move slower Kinetic Energy # RP stopped speed of light KEavg “hotter” note: area under the curve stays the same… area = total number of RP

Temperature and Maxwell-Boltzmann Distribution for a given sample (a collection of billions of billions of RP) “hotter” = _______________________________ know … Temperature – increases OR decreases OR stays the same Kinetic Energy of the RP – increases OR decreases OR stays the same or on average, the RP _______________________________ or, more ________________________________ and fewer _______________________ still same limits ___________ and ____________ thermal energy increases move faster KEavg KEavg “hotter” KEavg move faster move slower Kinetic Energy # RP stopped speed of light “colder” = _______________________________ know … Temperature – ________________________ Kinetic Energy of the RP – _________________ or on average, the RP _______________ or, more __________________________ and fewer _________________ thermal energy decreases decreases decreases # RP move slower move slower move faster “hotter” “colder” Kinetic Energy note: area under the curve stays the same… area = total number of RP

Temperature and Maxwell-Boltzmann Distribution for a given sample (a collection of billions of billions of RP) “hotter” = _______________________________ know … Temperature – increases OR decreases OR stays the same Kinetic Energy of the RP – increases OR decreases OR stays the same or on average, the RP _______________________________ or, more ________________________________ and fewer _______________________ still same limits ___________ and ____________ thermal energy increases move faster KEavg “hotter” Kinetic Energy # RP “colder” move faster move slower stopped speed of light “colder” = _______________________________ know … Temperature – ________________________ Kinetic Energy of the RP – _________________ or on average, the RP _______________ or, more __________________________ and fewer _________________ thermal energy decreases decreases decreases move slower move slower move faster slowest ? _________________ coldest ? _________________________ ________________________ stopped ALL RP are stopped absolute zero! link to EXCEL plots

Okay… so what…. What is Temperature? Measuring Temperature Temperature is some measure of _______________________________________ __________________________________________________________ KE = ½ × mv2 to measure the total KE of a sample directly one would need ________________________________________________ _________________________ Temperature is our indirect measure of thermal energy To measure temperature we use _________________________ the thermal energy of a sample that is reflected in the distribution of KE of the RP to measure the mass and speed of EACH RP impossible! RP are tooooooooo small to measure a thermometer The Thermometer

Okay… so what…. What is Temperature? KEavg #RP KE “cold” (RT) thermometer (KEavg _________) lower “hotter” (> RT) water (KEavg ________) higher KEavg for the hotter water, the RP are moving _________ on average than for the colder thermometer #RP faster KE

KEY whack!! when a fast moving RP hits a slower moving RP ________________________ the fast one moves slower transfer of KE whack!! and the slower one moves faster so,…. the average KE of the thermometer goes _____ and the average KE of the water goes __________ until ______________________________ up down they are the same NOTE: the thermal (KE) lost by the water = the thermal (KE) gained by the thermometer temp ___________ goes down temp ___________ goes up so, the temperature of what you are measuring the temperature of goes down (or up, if the sample is “cold” to start) the smaller the thermometer relative to the sample size, the less energy is transferred from the sample to the thermometer therefore, measuring the temperature, won’t change the temperature (as much)

KEY whack!! when a fast moving RP hits a slower moving RP ________________________ the fast one moves slower transfer of KE whack!! and the slower one moves faster so,…. the average KE of the thermometer goes _____ and the average KE of the water goes __________ until ______________________________ up down they are the same so,…. for the liquid in the thermometer if the KEavg , the RP move ___________________ hit ____________________ so, the RP “want” to ____________________ the only way to expand ? ________________________________ so, the liquid in the thermometer ___________________ faster harder spread out is up the thermometer tube rises hotter… RP move _________ …. hit _________ ….. more _____________ so, the liquid in the thermometer _________________ faster harder expansion goes up higher

KEY whack!! expansion of a liquid is proportional to its _________________ thermal energy whack!! so, the height of a column of liquid in a thermometer is proportional to its _________________________ thermal energy AND we record that height as the temperature (expansion) so,…. for the liquid in the thermometer if the KEavg , the RP move ___________________ hit ____________________ so, the RP “want” to ____________________ the only way to expand ? ________________________________ so, the liquid in the thermometer ___________________ faster harder spread out is up the thermometer tube rises hotter… RP move _________ …. hit _________ ….. more _____________ so, the liquid in the thermometer _________________ faster harder expansion goes up higher

So, what is a “Celcius”? a meter is _________________________ a gram is __________________________ a dozen is a Celcius (or a Farenheit) is ____________________ a unit of length a unit of mass a unit of count a unit of temperature what does that look like?

The Thermometer 100C 212F then, divide the space between 0C and 100C into 100 even increments… each is 1C that marks the degree of expansion of the liquid when it has the same thermal energy as freezing water 0C 32F Celsius labeled this as 0 C arbitrary arbitrary a “degree Celsius” is not a “anything” Celcius