1. LECTURE 6.2 – TEMPERATURE SCALES

2. Today’s Learning Targets LT 5.3 – I can define what STP is on an exit ticket LT 5.4 – 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 5.5 – I can define what absolute zero and relate it to the Kelvin temperature scale on an exit ticket LT 5.6 – I can convert between the Kelvin and Celsius temperature scales on an exit ticket LT 5.7 – I can explain Boyle’s Law, how it relates pressure and volume, and I can calculate pressure and volume values for a given problem on an exit ticket

3. What are the temperature scales?

4. 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

5. 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

6. What is STP?

7. 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

8. What is absolute zero?

9. 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.

10. 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.

11. How do we convert between Celsius and Kelvin

12. I. Converting Between Kelvin and Celsius To convert from Celsius to Kelvin: Kelvin = C o + 273 To convert from Kelvin to Celsius: Celsius = Kelvin – 273

13. Class Example It is 33 o C outside, what is this temperature in Kelvin?

14. Table Talk If I have something at 298 K, what temperature is it in Celsius?

15. Stop and Jot You measure a reaction at 1250 o C, what is the temperature in Kelvin?