1. CHAPTER 3 Temperature Energy and Heat 3.1 Temperature

2. 2 What is temperature? Why is temperature important in chemistry? How is energy related to temperature?

3. 3 3.1 Temperature Milk fat particles are being pushed around by water molecules

4. 4 3.1 Temperature At room temperature, atoms and molecules are in constant motion Brownian motion Milk fat particles are being pushed around by water molecules

5. 5 3.1 Temperature Grains of sand stand still…

6. 6 3.1 Temperature Grains of sand stand still… … but the individual atoms are in constant, random motion. kinetic energy: the energy of motion. temperature: a measure of the average kinetic energy of atoms or molecules.

7. 7 3.1 Temperature Random motion AFFECTS temperature Non random motion DOES NOT AFFECT temperature Random motionNon random motion

8. 8 3.1 Temperature Temperature is the measure of the average kinetic energy of atoms or molecules Some molecules have more kinetic energy than the average. Some molecules have less kinetic energy than the average. Temperature is an average Faster (more energy) Slower (less energy)

9. 9 3.1 Temperature Temperature is the measure of the average kinetic energy of atoms or molecules Some molecules have more kinetic energy than the average. Some molecules have less kinetic energy than the average. Temperature is an average

10. 10 3.1 Temperature Does everyone express temperature the same way?

11. 11 3.1 Temperature Temperature scales

12. 12 3.1 Temperature Water boils Water freezes How can we go back and forth between the two scales? Temperature scales

13. 13 3.1 Temperature What temperature in Celsius is the same as 100 o C?

14. 14 3.1 Temperature What temperature in Celsius is the same as 100 o F? Asked:Temperature in o C Given:100 o F Relationships:

15. 15 3.1 Temperature Asked:Temperature in o C Given:100 o F Relationships: Solve: Answer:100 o F is the same temperature as 37.8 o C What temperature in Celsius is the same as 100 o F?

16. 16 3.1 Temperature Asked:Temperature in o F Given:15 o C Relationships: What is the Fahrenheit equivalent of 15 o C?

17. 17 3.1 Temperature Asked:Temperature in o F Given:15 o C Relationships: Solve: Answer:15 o C is the same temperature as 59 o F. What is the Fahrenheit equivalent of 15 o C?

18. 18 3.1 Temperature Hot or cold? How can we accurately measure temperature?

19. 19 3.1 Temperature All thermometers are based on a physical property that changes with temperature. Thermal expansion: - Mercury thermometers - Alcohol thermometers Electrical sensors: - Thermistor - Thermocouple

20. 20 3.1 Temperature Thermal expansion: - Mercury thermometers - Alcohol thermometers Electrical sensors: - Thermistor - Thermocouple The temperature probe in the Lab-Master uses a thermistor All thermometers are based on a physical property that changes with temperature.

21. 21 3.1 Temperature kinetic energy: the energy of motion. temperature: a measure of the average kinetic energy of atoms or molecules.

22. 22 3.1 Temperature kinetic energy: the energy of motion. temperature: a measure of the average kinetic energy of atoms or molecules. What happens when the temperature is really, really low? What is the lowest possible temperature?

23. 23 3.1 Temperature Absolute zero At absolute zero the kinetic energy is essentially zero. 3 different scales

24. 24 3.1 Temperature We have already seen: Unit conversion

25. 25 3.1 Temperature + 273 - 273 Unit conversion

26. 26 3.1 Temperature Convert 27 o C into kelvins. Unit conversion

27. 27 3.1 Temperature Convert 27 o C into kelvins. Asked:Temperature in kelvin Given:27 o C Relationships: Unit conversion

28. 28 3.1 Temperature Convert 27 o C into kelvins. Asked:Temperature in kelvin Given:27 o C Relationships: Solve: Answer:300 K is the same temperature as 27 o C. Unit conversion

29. 29 3.1 Temperature Molecules are in constant, random motion. This affects temperature. Three temperature scales: