the system is the specific part of the universe that is of interest in the study. open mass &...
TRANSCRIPT
![Page 1: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/1.jpg)
The system is the specific part of the universe that is of interest in the study.
open
mass & energyExchange:
closed
energy
isolated
nothing
SYSTEMSURROUNDINGS
6.2
![Page 2: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/2.jpg)
DIRECTION OF HEAT FLOW
Surroundings
ENDOthermicqsys > 0
EXOthermicqsys < 0
System
Kotz, Purcell, Chemistry & Chemical Reactivity 1991, page 207
System
H2O(s) + heat H2O(l)
melting
H2O(l) H2O(s) + heat
freezing
![Page 3: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/3.jpg)
ENERGY OF ACTIVATION
![Page 4: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/4.jpg)
ENERGY OF ACTIVATION
![Page 5: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/5.jpg)
HEAT GAINED = HEAT LOST
DH = mDTCp
M= mass
DT= change in temperature
Cp= specific heat
![Page 6: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/6.jpg)
Caloric Values
Food joules/grams calories/gram Calories/gram
Protein 17 000 4000 4
Fat 38 000 9000 9
Carbohydrates 17 000 4000 4
Smoot, Smith, Price, Chemistry A Modern Course, 1990, page 51
1000 calories = 1 Calorie
"science" "food"
1calories = 4.184 joules
![Page 7: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/7.jpg)
HEATING CURVESTe
mp
erat
ure
(oC
)
40
20
0
-20
-40
-60
-80
-100
120
100
80
60
140
Time
Melting - PE
Solid - KE
Liquid - KE
Boiling - PE
Gas - KE
![Page 8: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/8.jpg)
A B warm iceB C melt ice (solid liquid)C D warm waterD E boil water (liquid gas)E D condense steam (gas liquid)E F superheat steam
HEATING CURVE FOR WATER(PHASE DIAGRAM)
140
120
100
80
60
40
20
0
-20
-40
-60
-80
-100
Tem
pera
ture
(oC
)
Heat
BP
MP
A
BC
D E
F
Heat = m x Cfus
Cf = 333 J/g
Heat = m x Cvap
Cv = 2256 J/g
Heat = m x DT x Cp, liquid
Cp = 4.184 J/goC
Heat = m x DT x Cp, solid
Cp (ice) = 2.077 J/goC
Heat = m x DT x Cp, gas
Cp (steam) = 1.87 J/goC
![Page 9: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/9.jpg)
HEATING CURVES
Temperature Changechange in KE (molecular motion) depends on heat capacity
• Heat Capacity– energy required to raise the temp of 1 gram of a
substance by 1°C– “Volcano” clip -– water has a very high heat capacity
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
![Page 10: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/10.jpg)
HEATING CURVES
Phase Changechange in PE (molecular arrangement)temp remains constant
• Heat of Fusion (Hfus)– energy required to melt 1 gram of a substance at its
m.p.
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
![Page 11: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/11.jpg)
HEATING CURVES
Heat of Vaporization (Hvap)energy required to boil 1 gram of a substance at its b.p.
usually larger than Hfus…why?
• EX: sweating, steam burns, the drinking bird
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
![Page 12: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/12.jpg)
HUMOR
A small piece of ice which lived in a test tube fell in love with a Bunsen burner.
“Bunsen! My flame! I melt whenever I see you” said the ice.
The Bunsen burner replied” “It’s just a phase you’re going through”.
![Page 13: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/13.jpg)
CH4 + 2 O2 ® CO2 + 2 H2O + 802.2 KJ
If 10. 3 grams of CH4 are burned completely, how much heat will be produced?
15
10. 3 g CH4
16.05 g CH4
1 mol CH4
1 mol CH4
802.2 kJ
= 514 kJ
![Page 14: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/14.jpg)
ENTROPY (ABBREVIATED “S”)
Entropy is a measure of disorder, and is measured in units of J/mol.K; and there are no negative values of entropy
Entropy (S) is a measure of the randomness or disorder of a system.
![Page 15: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/15.jpg)
- Page 570
Entropy of the gas is greater than the solid or liquid
Entropy is increased when a substance is divided into parts
Entropy increases when there are more product molecules than reactant molecules
Entropy increases when temperature increases
![Page 16: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/16.jpg)
![Page 17: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/17.jpg)
Entropy (S) is a measure of the randomness or disorder of a system.
order SdisorderS
If the change from initial to final results in an increase in randomness
DS > 0
For any substance, the solid state is more ordered than the liquid state and the liquid state is more ordered than gas state
Ssolid < Sliquid << Sgas
H2O (s) H2O (l) DS > 0
18.3
![Page 18: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/18.jpg)
EQUAL MASSES OF HOT AND COLD WATER
Thin metal wall
Insulated box Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 291
![Page 19: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/19.jpg)
WATER MOLECULES IN HOT AND COLD WATER
Hot water Cold Water90 oC 10 oC
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 291
![Page 20: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/20.jpg)
WATER MOLECULES IN THE SAME TEMPERATURE WATER
Water(50 oC)
Water(50 oC)
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 291
![Page 21: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/21.jpg)
The amount of heat required to raise the temperature of one gram of substance by one degree Celsius.
Specific Heat
![Page 22: The system is the specific part of the universe that is of interest in the study. open mass & energyExchange: closed energy isolated nothing SYSTEMSURROUNDINGS](https://reader036.vdocuments.net/reader036/viewer/2022062801/56649e635503460f94b5f44c/html5/thumbnails/22.jpg)
In football, as in Hess's law, only the initial and final conditions matter.A team that gains 10 yards on a pass play but has a five-yard penalty,has the same net gain as the team that gained only 5 yards.
initial positionof ball
final positionof ball
10 yard pass
5 yard penalty
5 yard net gain