1. Celsius & Kelvin Temperature Scales
100
Kelvins
373 K
273 K
0 K
Boiling point
of water
100oC
100
Celsius
degrees
Freezing point
of water
0oC
Students need to realize that the Celsius scale is based on the Kelvin scale.
1o Celsius and 1 Kelvin are equal size units
It is not possible to have a temperature below 0 Kelvin (absolute zero).
Absolute
zero
-273oC

2. Temperature is Average Kinetic Energy
“HOT” “COLD”
Average Kinetic Energy is temperature. Mathematically, kinetic energy (avg) = ½ mv2.
Total kinetic energy is what we call heat.
Heat is measured with an instrument called a calorimeter.
Temperature is measured with an instrument called a thermometer.
Fast Slow
Kinetic Energy (KE) = ½ m v 2
*Vector = gives direction and magnitude

3. Temperature Scales Fahrenheit 212 oF 180 oF 32 oF Celcius 100 oC 0 oC
Kelvin
373 K
100 K
273 K
Boiling point
of water
An absolute English scale exists called the Rankin scale.
On the Kelvin scale it is NOT possible to have a negative temperature.
Daniel Gabriel Fahrenheit ( ), German physicist invented mercury thermometer in 1724
ice bath with salt = 0oF
body temperature =96oF
freezing point (of water) = 32oF
boiling point (of water) = 212oF
Anders Celsius ( ), Swedish astronomer modified mercury thermometer in 1742
freezing point (of water) = 0oC
boiling point (of water) = 100oC
A Celsius degree is also called a centigrade.
William Thomson ( ), English physicist knighted Lord Kelvin in 1848
proposed a scale based on lowest possible temperature
freezing point (of water) = 273 K
boiling point (of water) = 373 K
coldest possible temperature = 0 K or absolute zero = oC
Freezing point
of water
Notice that 1 kelvin degree = 1 degree Celcius

4. Kelvin Scale blue 5250 K Sunlight 5000 K PIAA Plasma Blue
white
yellow
4300 K PIAA HID Bulb
5000 K PIAA Plasma Blue
5250 K Sunlight
4150 K PIAA Xtreme White
3800 K PIAA Super White
3200 K Halogen Bulb
2600 K Incandescent Bulb

5. Temperature Scales
An absolute English scale exists called the Rankin scale.
On the Kelvin scale it is NOT possible to have a negative temperature.
Daniel Gabriel Fahrenheit ( ), German physicist invented mercury thermometer in 1724
ice bath with salt = 0oF
body temperature =96oF
freezing point (of water) = 32oF
boiling point (of water) = 212oF
Anders Celsius ( ), Swedish astronomer modified mercury thermometer in 1742
freezing point (of water) = 0oC
boiling point (of water) = 100oC
A Celsius degree is also called a centigrade.
William Thomson ( ), English physicist knighted Lord Kelvin in 1848
proposed a scale based on lowest possible temperature
freezing point (of water) = 273 K
boiling point (of water) = 373 K
coldest possible temperature = 0 K or absolute zero = oC
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 136

6. Compare Celsius to Fahrenheit
oF – 32 = 1.8 oC
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 139

7. Converting 70 degrees Celsius to Kelvin units.
oC = K
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 137

8. 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 (oC)
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 oC and boiling is 100 oC.
Fahrenheit scale (oF)
Mercury and alcohol thermometers rely on thermal expansion
Anders Celsius ( )
Lord Kelvin (William Thomson)
Daniel Gabriel Fahrenheit ( )
Daniel Gabriel Fahrenheit ( ), German physicist invented mercury thermometer in 1724
ice bath with salt = 0oF
body temperature =96oF
freezing point (of water) = 32oF
boiling point (of water) = 212oF
Anders Celsius ( ), Swedish astronomer modified mercury thermometer in 1742
freezing point (of water) = 0oC
boiling point (of water) = 100oC
A Celsius degree is also called a centigrade.
William Thomson ( ), English physicist knighted Lord Kelvin in 1848
proposed a scale based on lowest possible temperature
freezing point (of water) = 273 K
boiling point (of water) = 373 K
coldest possible temperature = 0 K or absolute zero = oC

9. 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
Cracks in sidewalk.
COLD
HOT

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

11. Water Molecules in Hot and Cold Water
Hot water Cold Water
90 oC oC
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 291

12. Water Molecules in the same temperature water
(50 oC)
Water
(50 oC)
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 291

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

14. Molecular Velocities the Maxwell speed distribution
molecules sorted by speed
many different molecular speeds
Fractions of particles
the Maxwell speed distribution
speed

15. Temperature vs. Heat Different Alike Different Topic Topic Have
Kinetic
Energy
Measured
with a
Thermometer
Measured
with a
Calorimeter
Topic
Topic
Average
Kinetic
Energy
A Property of
Matter
Total
Kinetic
Energy
Heat
Temperature
Melting point and boiling point are both INTENSIVE properties of matter (related to temperature)
Heat is an EXTENSIVE property of matter (the more wood you burn...the more heat is produced)
oCelcius
(or Kelvin)
Joules
(calories)

16. Conservation of Matter
Conservation of Matter: Matter can neither be created nor destroyed.
Atoms rearrange in chemical reactions – the macroscopic (what we see) view of things may appear as though ‘new’ matter has been created. However, at the microscopic level we would see only that compounds and molecules have been broken apart and rearranged into new compounds and molecules (from the same atoms we started with).
This is a demonstration using potassium iodide mixed with lead nitrate to yield a precipitate of lead (II) iodide and soluble potassium nitrate.
A small test tube filled with lead nitrate is resting inside the Erlenmeyer flask. When inverted, the chemical reaction occurs.
No new material is added to the flask - it is a closed system. During the chemical reaction, atoms are rearranged.
The product has different properties (i.e. it changes from colorless to yellow) than the reactants.
Lead (II) iodide is very toxic. Dispose of waste in a responsible manner.
Lead (II) iodide is also the pigment added to road stripe paint.
Reactants yield Products

17. Heavy Metal Poisoning TREATMENT: Chelation therapy
EDTA (ethylenediamine tetra acetic acid)
Exposure to mercury
made the Hatter “mad”.
Look for links to web sites for more information:
Chelation therapy
Toxicity of heavy metals
Lead is no longer added to house paint.
Green-treated wood no longer uses arsenic and is now labeled AC-2 (second generation without arsenic).
EDTA is added as a preservative to canned foods to remove any extra metal ions present.
Arsenic treated lumber.
‘Green-treated’ wood
will not rot outdoors
for 50 years.
Eating chips of lead paint
causes brain damage.