Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the...
-
Upload
darlene-snow -
Category
Documents
-
view
215 -
download
0
Transcript of Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the...
![Page 1: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/1.jpg)
Entropy - The Drive Toward Maximum Randomness
•Chemical reactions are driven by 2 main forces:•the drive to minimize stored energy (enthalpy)•the drive to maximize randomness (entropy)•Substances, over time, will become as random and disorganized as possible
![Page 2: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/2.jpg)
Observe what happens to randomness when a substance is heated and/or changes phases.
![Page 3: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/3.jpg)
![Page 4: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/4.jpg)
![Page 5: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/5.jpg)
![Page 6: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/6.jpg)
![Page 7: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/7.jpg)
![Page 8: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/8.jpg)
![Page 9: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/9.jpg)
![Page 10: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/10.jpg)
![Page 11: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/11.jpg)
![Page 12: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/12.jpg)
![Page 13: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/13.jpg)
![Page 14: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/14.jpg)
![Page 15: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/15.jpg)
![Page 16: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/16.jpg)
![Page 17: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/17.jpg)
![Page 18: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/18.jpg)
![Page 19: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/19.jpg)
![Page 20: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/20.jpg)
![Page 21: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/21.jpg)
![Page 22: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/22.jpg)
![Page 23: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/23.jpg)
![Page 24: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/24.jpg)
![Page 25: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/25.jpg)
![Page 26: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/26.jpg)
![Page 27: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/27.jpg)
![Page 28: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/28.jpg)
![Page 29: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/29.jpg)
![Page 30: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/30.jpg)
![Page 31: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/31.jpg)
![Page 32: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/32.jpg)
![Page 33: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/33.jpg)
![Page 34: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/34.jpg)
![Page 35: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/35.jpg)
![Page 36: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/36.jpg)
![Page 37: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/37.jpg)
![Page 38: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/38.jpg)
![Page 39: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/39.jpg)
![Page 40: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/40.jpg)
![Page 41: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/41.jpg)
![Page 42: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/42.jpg)
![Page 43: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/43.jpg)
![Page 44: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/44.jpg)
![Page 45: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/45.jpg)
![Page 46: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/46.jpg)
![Page 47: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/47.jpg)
![Page 48: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/48.jpg)
![Page 49: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/49.jpg)
![Page 50: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/50.jpg)
![Page 51: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/51.jpg)
![Page 52: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/52.jpg)
![Page 53: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/53.jpg)
![Page 54: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/54.jpg)
![Page 55: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/55.jpg)
![Page 56: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/56.jpg)
![Page 57: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/57.jpg)
•Entropy is the word used to describe this randomness•because of the drive toward maximum entropy a highly organized state has a low probability•the probability that a given substance will exist in a specific state is known as its molar entropy and has the symbol S with units of J/molK•the larger the number the greater the probability of existence
![Page 58: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/58.jpg)
For each of the following is entropy increasing or decreasing.H2O(l) + heat -----> H2O(g)
IncreasingC2H6(g) + 7/2O2(g) ----> 2CO2(g) + 3H2O(g)Increasing, 4.5 molecules to 5 moleculesCaCO3(s) ---> CaO(s) + CO2(g)Increasing, solid to gas, 1 particle to 2 particles2Mg(s) + O2(g) ---> 2MgO(s)Decreasing, 3 particles to 2 particles, g to sAgNO3(aq) + KCl(aq) --> AgCl(s) + KNO3(aq)Decreasing, 4 mobile ions to 2 mobile ions
Movie1Movie2
![Page 59: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/59.jpg)
Entropy ChangesS = S(products) - S(reactants)S values for elements are NOT assigned an arbitrary value of zeroWhen S is negative - entropy is decreasing, this change is not favoured (less randomness) S is positive- entropy is increasing, this change is favoured (more randomness)
![Page 60: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/60.jpg)
Chemical Reactions have a tendency to be spontaneous when the H is negative and the S is positive. In other words the randomness of the system is increasing and the amount of stored energy is decreasing.
![Page 61: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/61.jpg)
Using Entropy values from pg. 798 consider the combustion of liquid benzene (C6H6). Water vapour is the product.
C6H6 (l) +7.5O2 (g) =>6CO2 (g) + 3H2O(g)
S = S(products) - S(reactants)
= (6 mol x 213.78 J/molK + 3 mol x 188.84 J/molK) - (1 mol x 173 J/molK + 7.5 mol x 205.3 J/molK)= 136 J/ K
since S is positive the entropy drive is favourable
![Page 62: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/62.jpg)
Free EnergyIn nature enthalpy and entropy operate simultaneously and to determine if a given chemical reaction will or will not occur we must look at the two driving forces togetherIf H is -ve and S is +ve = spontaneousIf H is +ve and S is -ve = not spontaneousIf one drive is favourable and the other is not it is not clear whether it is or isn’t spontaneous
![Page 63: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/63.jpg)
When enthalpy and entropy oppose one another, their relative importance in determining spontaneity is far from obvious. In addition, temperature is a 3rd factor that influences the direction of a spontaneous change.
![Page 64: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/64.jpg)
Chemical Reactions are spontaneous when the answer to this equation is negative
H - TSwhere T is temperature in Kso when TS > H the reaction is spontaneous. The difference is called Gibb’s (G) Free EnergyGH - TS
G =
![Page 65: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/65.jpg)
At what temperature is this reaction spontaneous?
H2O(l) -----> H2O(g) Recall when TS > H the reaction is spontaneous. Go to the tables to solve for T. T > H/ST>(-242 kJ/mol x 1 mol - (-286 kJ/mol x 1mol) 188.7 J/molK x 1 mol - 69.96 J/molK x 1 mol
T> (44 kJ)/(0.11874 kJ/K)T> 3.7 x 102 K
![Page 66: Entropy - The Drive Toward Maximum Randomness Chemical reactions are driven by 2 main forces: the drive to minimize stored energy (enthalpy) the drive.](https://reader035.fdocuments.us/reader035/viewer/2022062422/56649ec55503460f94bcfea2/html5/thumbnails/66.jpg)
HomeworkRead pg 494 - 508QuestionsPg. 498 # 1Pg. 508 #2Pg. 512 # 1-11