chapter 4 (cic) and chapter 5, 8 (ctcs) read in ctcs chapter 5.1,3-4, 8.9 problems in ctcs: 5.3, 13,...
TRANSCRIPT
![Page 1: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/1.jpg)
Chapter 4 (CIC) and Chapter 5, 8 (CTCS)
• Read in CTCS Chapter 5.1,3-4, 8.9
• Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69
![Page 2: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/2.jpg)
Global Warming (CO2) Fuel• Fuel’s are typically fossil fuels (crude oil, coal)
• Gasohol is a mixture of ethanol and gasolineCH2=CH2 + H2O CH3CH2OH
C6H12O6 CH3CH2OH + CO2
• Does EtOH give same performance as gasoline? Does EtOH give the same amount of energy per gram?
• 1st Law – If we have Conservation of Energy, why are worried about depleting our resources?
![Page 3: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/3.jpg)
Annual US Energy Consumption From Various Sources
![Page 4: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/4.jpg)
Combustion• All but two of those energy sources were based
on combustion giving CO2 as a byproduct• Energies can be obtained from a calorimeterQ: Determine the heat of combustion for a gram
of natural gas (CH4) compared to a gram of butane (C4H10) if their heats of combustion are –802.3 and –2658.4 kJ/mol respectively.
A:-50.01 kJ/g and –45.74kJ/g
![Page 5: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/5.jpg)
Energy Diagram
Reactants
ProductsEnt
halp
y
Reaction Progress
Hrxn
![Page 6: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/6.jpg)
• Where does the exothermic energy come from?
• When bonds are broken, energy is required• When bonds are made, energy is released• Compare the bond strengths in the equation
above (See Table 8.4 - pg 289)• The products are:
– More stable– Lower in Energy– Have stronger bonds
H
CH
H
+ 2O O O C O O2H HH +
![Page 7: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/7.jpg)
• CO2 and H2O are too stable (have bonds that are too strong) to decompose and give off more energy
Q: Could you use ozone as a fuel? How much energy is released/g of ozone? (Use bond energies to calculate)
A: -2.11 J/g (-2.96 kJ/g according to Hºf)
• Bond Energies are averages of gas moleculesHºf – enthalpy of formation in standard state (º)
![Page 8: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/8.jpg)
Q: Using bond energies, calculate the heat of reaction for the combustion of molecular hydrogen and 1 mol of oxygen to form gaseous products
A: -485 kJ (actual = -483.6 kJ)
Q: Would you expect a more endo- or exo-thermic reaction if the products were liquid?
![Page 9: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/9.jpg)
• H2O(g) H2O(l) H = negative,WHY?
• 2 H2(g) + O2(g) 2 H2O(l)
• Can’t use bond energies!Hºrxn = -571.7 kJ
• Spontaneity (G)– If you have a large negative H, you can assume
spontaneity
Q: What are some of the strongest bonds?
![Page 10: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/10.jpg)
• Triple: NN, CO; Double: C=O; Single: O-H, Si-O
• This suggests that these bonds would have trouble reacting
2 CO + O=O 2 O=C=O Hºrxn= -566 kJ
• Explosives– Should have many weak bonds– Ideally have all atoms of reaction self contained– Need to be stable enough to work with– Should create gaseous molecules
![Page 11: Chapter 4 (CIC) and Chapter 5, 8 (CTCS) Read in CTCS Chapter 5.1,3-4, 8.9 Problems in CTCS: 5.3, 13, 15, 22, 23, 29, 35, 90, and 8.63, 65, 67, 69](https://reader035.vdocument.in/reader035/viewer/2022062314/56649e6b5503460f94b68f05/html5/thumbnails/11.jpg)
• Nitroglycerin
• What are the products of decomposition?
Q: What is the Hrxn/mol of nitro? (why not Hºrxn?)
A: -1782 kJ
CH2 O
HC
CH2
O
O
NO2
NO2
NO2