1. Temperature v. Heat

2. Celsius & Kelvin Temperature Scales Boiling point of water Freezing point of water Absolute zero Celsius 100 Celsius degrees 100 o C 0oC0oC -273 o C Kelvin 100 Kelvins 373 K 273 K 0 K

3. Temperature is Average Kinetic Energy Fast Slow “HOT” “COLD” Kinetic Energy (KE) = ½ m v 2 *Vector = gives direction and magnitude

4. Temperature Scales Fahrenheit 212 o F 180 o F 32 o F Celcius 100 o C 0 o C Kelvin 373 K 100 K 273 K Boiling point of water Freezing point of water 1 kelvin degree = 1 degree Celcius Notice that 1 kelvin degree = 1 degree Celcius

5. Temperature Scales Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 136

6. Compare Celsius to Fahrenheit o F – 32 = 1.8 o C Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 139

7. Temperature Scales Temperature can be subjective and so fixed scales had to be introduced. The boiling point and freezing point of water are two such points. Celsius scale ( o C) –The Celsius scale divides the range from freezing to boiling into 100 divisions. –Original scale had freezing as 100 and boiling as 0. –Today freezing is 0 o C and boiling is 100 o C. Fahrenheit scale ( o F) Mercury and alcohol thermometers rely on thermal expansion

8. Thermal Expansion Most objects e-x-p-a-n-d when heated Large structures such as bridges must be built to leave room for thermal expansion All features expand together COLD HOT Cracks in sidewalk.

9. Equal Masses of Hot and Cold Water Thin metal wall Insulated box Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 291

10. Water Molecules in Hot and Cold Water Hot water Cold Water 90 o C 10 o C Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 291

11. Water Molecules in the same temperature water Water (50 o C) Water (50 o C) Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 291

12. Heat versus Temperature Kinetic energy Fractions of particles lower temperature higher temperature TOTAL Kinetic ENERGY = Heat

13. Temperature vs. Heat Measured with a Calorimeter Total Kinetic Energy Joules (calories) Measured with a Thermometer Average Kinetic Energy o Celcius (or Kelvin) Alike Different A Property of Matter Have Kinetic Energy Heat Different Topic Temperature thermometer calorimeter

14. Conservation of Matter Reactants yield Products