Catalyst
1. How is pressure created?
2. Give 3 units that pressure is measured with
3. How does the motion of gas molecules
explain diffusion?
End
JUST HOW COLD CAN IT GET?
Justify – TPS
• What is the coldest possible temperature?
Lecture 6.3 – Temperature Scales
Today’s Learning Targets
• LT 6.3 – I can define what STP is on an exit ticket
• LT 6.4 – I can discuss how the kinetic energy of a gas
molecules is related to the temperature of the gas mixture
on an exit ticket
• LT 6.5 – I can define what absolute zero and relate it to the
Kelvin temperature scale on an exit ticket
• LT 6.6 – I can convert between the Kelvin and Celsius
temperature scales on an exit ticket
What are the temperature scales?
I. Temperature
• The temperature that we
feel is created by the
movement of atoms.
• The movement of gas
molecules in the air creates
our observable temperature
• The temperature is a
measurement of the average
energy of a sample
II. Temperature Scales
• The 2 main
temperature scales in
chemistry are the
Celsius and Kelvin
scales
• The Celsius scale sets
the freezing point of
water at 0 oC and the
boiling point of water
at 100 oC
What is STP?
I. STP
• When working with gases,
reactions are normally
carried out under standard
temperature and pressure
or STP
• STP is defined as 273 K and 1
atm
What is absolute zero?
I. Kelvin Scale
• The other unit of
temperature used in
chemistry is the Kelvin
scale.
• The Kelvin scale sets 0 K
as being absolute zero.
II. Absolute Zero
• Absolute zero is the
temperature at which all
molecular motion stops.
• Coldest possible
temperature
• It is impossible to go
below absolute zero (0 K)
because molecular
motion has stopped at
this point.
How do we convert between Celsius and Kelvin
I. Converting Between Kelvin and Celsius
• To convert from Celsius to Kelvin:
Kelvin = Co + 273
• To convert from Kelvin to Celsius:
Celsius = Kelvin – 273
Class Example
• It is 33 oC outside, what is this temperature in
Kelvin?
Table Talk
• If I have something at 298 K, what
temperature is it in Celsius?
Stop and Jot
• You measure a reaction at 1250 oC, what is the
temperature in Kelvin?
Got it?
–Warmest November day in LA:
37.7° C (100° F) on November 1,
1966.
–Coldest November day in LA: 1.1 °
Convert
these
to Kelvin
C (34°
F) ontemperatures
November 19, 1886.
SUMMARIZE
Gas Phase/Absolute Zero Game
• A fun take on red light,
green light.
• You are a molecule
• When the person who is
the caller says gas phase
you move
• When the person who is
the caller says absolute
zero you stop
• Why do molecules stop at
absolute zero?
Exit Ticket
1. What is the coldest possible temperature?
What happens at this point?
2. What are the temperature and pressure for
STP?
Rate Yourself
• Rate yourself 1 – 4 on LT 6.1 to 6.7
Closing Time
• Homework 6.3 – Temperature Scales