Chapter 6 Lecture Outline
6.1 Chemical Hand Warmers
6.2 The Nature of Energy: Key Definitions
- Video Clip (George Gobel's Home Page, local)
- Limiting Reagent problem
Introduction to Thermodynamics
- Gummy Bear Animation (
© Saunders, 1997)
- What is energy (ability to do work, relative)
- Kinetic energy Ek = 1/2*m*v2 (Throw Chalk)
- Potential energy Ep = mgh (Drop Chalk)
- Chemical energy (stored in bonds)
- Electrolysis of water (demonstrate)
- Dissolving salt (cold)
- Combustion of gasoline
- Combustion of H2 and O2 (demonstrate)
- calorie (1 gram of water 1 C)
- Joule (SI Unit) kg m2/s2
- cal = 4.184 J
6.3 The First Law of Thermodynamics: There is No Free Lunch
- The law of conservation of energy.
- Energy content of the universe is constant.
- Energy can be neither created nor destroyed.
- No perpetual motion machines.
- Problems are worked in terms of the internal energy of a system E
- We can only measure the change in energy, /\E.
- What is a system?
- The change in internal energy is also related to heat (q) and work (w)
E = q + w
- Concept of Change, Altitude Analogy
- Arbitrary Reference Point (sea level)
- Sign is significant
- Independent of Path
- Introduce Energy Level Diagram
6.4 Quantifying Heat and Work
- Heat Transfer
- Macro scale video (
© Saunders, 1997)
- Micro scale animation (
© Saunders, 1997)
- Discuss Energy, Heat, and Temperature
- Example Problems
6.5 Measuring E for Chemical Reactions: Constant-Volume Calorimetry
6.6 Enthalpy: The Heat Evolved in a Chemical Reaction at Constant Pressure
- q = heat (Thermal Energy)
- w = work (P*V, change in volume, N=kg m sec-2, Pa=kg m-1 sec-2)
- [delta] E = q + w (Energy is heat plus work)
- IF volume is constant, no work, [delta] E = q
- IF pressure is constant, [delta] H = qp
6.7 Constant-Pressure Calorimetry: Measuring Hrxn
6.8 Relationships involving Hrxn
6.9 Enthalpies of Reaction from Standard Heats of Formation
- Misc terms
- [delta] H Change in Enthalpy
- [delta] H° Change in Enthalpy at standard state
- [delta] Hf° Enthalpy of Formation at standard state
- Standard State 25C (298K) and 1 bar
- [delta] Hrxn = Hfinal - Hinitial
- Energy Diagram
- State Properties
- physical state (ie: solid or liquid)
- Hess's Law Problems(sum of steps).
- Use energy level diagram to calcuate /\H for the following reaction: C (s) + 2 H2 -> CH4
- [delta] H for production of 500 g CCl4 based upon [delta] Hf and the reaction:
CH4(g) + 4 Cl2 (g) -> CCl4 (l) + 4 HCl (g)
- Calculate [delta] Hrxn for the production of hydrazine rocked fuel and the amount of energy required to produce 1.00 kg of hydrazine formed from the reaction: (Ebbing page 252)
N2 (g) + 2H2 (g) -> N2H4 (l)
- Calculate [delta] Hrxn for the combustion of gasoline and determine how much energy is released by burning 1 gallon of gasoline? (Density 0.7025 g/cm3)
2 C8H18 + 25 O2 -> 16 CO2 + 18 H2O
- Calculate how much energy is required to produce 150 g of glucose ([delta]Hf = -1274 kJ mole-1, Aitkins) from CO2 and H2O
- The Ostwand process for nitric acid involves the following steps:
4 NH3 (g) + 5 O2 (g) -> 4 NO (g) + 6 H2O (g)
2 NO (g) + O2 (g) -> 2 NO2 (g)
3 NO2 (g) + H2O (l) -> 2 HNO3 (aq) + NO (g)
- Find [delta] H for each reaction.
- Balance total reaction and find [delta] H.
- How much energy is required to produce 1000 kg of nitric acid?
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Last Updated Friday, May 25, 2001 1:59:43 PM