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 o C and the boiling point of water at 100 o C

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 = C o To convert from Kelvin to Celsius: Celsius = Kelvin – 273

Class Example It is 33 o C 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 o C, what is the temperature in Kelvin?

Got it? – Warmest November day in LA: 37.7° C (100° F) on November 1, – Coldest November day in LA: 1.1 ° C (34° F) on November 19, Convert these temperatures to Kelvin

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