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| Code: | Chem 131C |
| Subject: | Chemistry |
| Topic: | Thermodynamics |
| Views: | 42,733 |
Chem 131C: Thermodynamics and Chemical Dynamics
Video Lectures
Displaying all 27 video lectures.
Lecture 1 Play Video |
Syllabus, Homework, & Lectures Recorded on April 11, 2012. Slide Information 00:20 - Introduction 00:32 - Curvature of the Conical Intersection Seam: An Approximate Second-Order Analysis 01:15 - Announcements 02:24 - Syllabus 13:50 - Lectures 15:58 - Results 17:41 - More Information about Lecture Format ("I use powerpoint...") 18:47 - Example of Lecture Format 19:23 - Each Week-Three Inputs (Lecture Format) 21:36 - What Are We Going to Learn This Quarter? 25:50 - What's in this Lecture? 25:58 - Quantum Mechanics is Discovered (Timeline) 26:20 - Pioneers in Quantum Mechanics (Timeline) 31:26 - James Clerk Maxwell 31:44 - Maxwell Invented Free Color Photography 31:57 - First color photograph Example 32:25 - Ludwig Boltzmann 33:11 - Boltzmann's Grave in Vienna 33:23 - Willard Gibbs: 35:05 - Grove Street Cemetery: 35:35 - Statistical Mechanics: Why do We Need it? 36:40 - Using Thermodynamics 37:15 - Statistical Mechanics Establishes this Connection 37:54 - The Free Energy of Ammonia 38:32 - "Elements of Statistical Thermodynamics" Book (by Leonard K. Nash) 39:32 - Books to Buy: 40:16 - ...Consider a Molecule Having Evenly Spaced Energy Levels 40:42 - We can approximate its state distribution as shown here: 40:54 - The quantum numbers of these evenly spaced (by hv...) 40:58 - ...now imagine that you have a 3-dimensional array molecules... 42:06 - Now let's add three quanta of energy to these three molecules. 43:30 - Microstate 43:38 - Ten microstates in total: 43:42 - The 10 microstates exist in just three configurations. 44:46 - Examples of Notations (Example II) 45:08 - Examples of Configurations (I, II, III) 45:20 - Counting the Microstates Associated with Each Configuration 49:14 - Formula for Determining Total Number of Microstates |
Lecture 2 Play Video |
The Boltzmann Distribution Law Recorded on April 4, 2012. Slide Information: 01:48 - About Quiz I 04:17 - The Boltzmann Distribution Law 04:21 - What's in This Lecture? 04:44 - Consider a Harmonic Oscillator-Like State Distribution 05:04 - Now imagine that you have a 3-dimensional array of these "molecules" 06:28 - now let's add three quanta of energy to these three molecules. 06:52 - One option is to put all three quanta into one molecule. 07:40 - We shall refer to ech of these possibilities as a microstate; 07:44 - Notation for Specifying a particular configuration (families of microstates) 08:50 - Configuration Example 09:04 - Configuration Example (I, II, III) 09:59 - Configuration II Example 11:11 - Configuration I Example 14:13 - Configuration III Example 14:41 - Formula - The Number of Microstates, W, for a Particular Configuration 15:09 - Example: Consider a system of eight molecules containing four energy quota... 17:16 - How about 5 quanta in ten "molecules" (example)? 19:07 - How about 5 quanta in ten "molecules" (example II)? 20:27 - Curious: configuration VI is favored by more than 2:1 compared the others... 21:31 - Now what happens as we increase the number of molecules? 22:14 - Flipping a Coin Example 22:55 - Flipping a Coin Outcomes and Possibilities 23:24 - N coin flips, the preference of the system for the most probably configuration increases with N... 27:32 - Question: What does the big "N" stand for on Cornhuskers Stadium? 27:57 - Knowledge of this highly preferred configuration equates to knowledge of the system as a whole! 28:17 - Configuration VI is favored by more than 2:1 compared with any other... 28:21 - ...two ways to find this highly preferred configuration... 28:41 - Knowledge of this highly preferred configuration equates to knowledge of the system as a whole! 29:48 - Consider an isolated (N & Q constant) macroscopic (N large etc.) assembly of N... 31:41 - Graphic Representation 33:28 - Number of Microstates Before and After 35:46 - ...substituting from the expressions for energy defined earlier we have... 37:25 - ...this means that the left and right sides of this equality are constants, call this constant B (beta) 39:31 - The Boltzmann Distribution Law (Formula) 41:45 - Example (Solving for N) 43:07 - Molecular Partition Function, q: Two Versions (Figure) 44:17 - Example: What are the relative populations of the states of a two level system... 47:33 - Example: A certain atom has a threefold degenerate ground level... 52:33 - How much Thermal Energy is in the System? (Figure) Required attribution: Penner, Reginald Thermodynamics and Chemical Dynamics 131C (UCI OpenCourseWare: University of California, Irvine), http://ocw.uci.edu/courses/chem_131c_thermodynamics_and_chem... [Access date]. License: Creative Commons Attribution-ShareAlike 3.0 United States License. (http://creativecommons.org/licenses/by-sa/3.0/us/deed.en_US). |
Lecture 3 Play Video |
Energy and q (The Partition Function). Recorded on April 6, 2012. Slide Information 00:19 - Example-A certain atom has a threefold degenerate ground level... 01:02 - Function for Calculating Degeneracy of Energy Levels 01:24 - Sum of Three Energy Levels 03:35 - We need to calculate the thermal energy kT, in units... 04:22 - Energy Level Diagram 07:20 - Example: The four lowest electronic energy levels of atomic C have energies and degeneracies as follows... 07:51 - Equation: Partition Function 08:32 - In this case, q will have four terms - one for each state 08:49 - How to Calculate the Four Terms 09:59 - Example: 9.27 of 14 total states in C... 10:24 - does this makes sense (calculating thermal energy again) 10:56 - Diagram-Electronic States of Carbon 12:53 - now find the fractional population of each level for C... 14:51 - Diagram: ...now, it will be obvious to you that W must depend on energy... 15:45 - Partition Function (W must depend on energy, but how?) 20:03 - Example: the NO molecule has a doubly degenerate excited electronic level... 21:03 - Diagram--Wave Numbers 22:05 - Example - The NO molecule has a doubly degenerate excited electronic level... (continued) 22:40 - Plot (Diagram) 23:38 - Calculating Term Populations |
Lecture 4 Play Video |
Entropy Recorded on April 9, 2012. Slide Information 00:05 - Intro Slide: Entropy 00:15 - Announcements 01:00 - Quiz I histogram 01:03 - What's in this Lecture? 01:17 - Six things we have learned about Statistical Mechanics 04:17 - Boltzman Distribution Law Diagram and Definition 04:21 - Things we Have Learned About Statistical Mechanics so Far 04:32 - The Boltzmann Distribution Law Formula (Diagram) 06:34 - Formula/Equation Diagram (the average internal energy of each of N molecules) 08:11 - Equation Diagram ("so q contains information about the averge internal energy of our system.") 09:13 - Diagram: (The NO molecule) 10:01 - Graph (b) the electronic contribution to the molar internal energy at 300K. 11:20 - Graph (b) - Evaluating formula 13:58 - (Does formula and solution make sense?) 15:37 - Chart (On p. 429 of your book, three types of ensembles are discussed as follows:) 16:24 - Chart: Microcanonical Ensembles 16:34 - About Microcanonical Ensembles 17:14 - Graph: Example: NO - it's obvious we're talking about one molecule here... 17:54 - Diagram: The Boltzmann Distribution Law in terms of the molecular partition function, q 18:14 - so q asks the question: 18:47 - Canonical Ensembles 19:38 - Well, consider just two molecules, call them a and b... 21:28 - this is the appropriate expression when the N units are distinguishable. 22:48 - Equations for two States (for two distinguishable units, we CAN tell the difference...) 24:35 - Chart: What if we had three molecules, a, b,c... 25:53 - Chart: Ensemble name| What's Constant | Its Partition Function 27:01 - Experiment: Place 100 nickels into a shoes box, all heads up 29:00 - Experiment: 1. Place 100 nickels into a shoes box, ALL heads up... 30:34 - Experiment Conclusion: "For any isolated assembly, we can always predict... 31:00 - For any isolated assembly... 31:55 - Formula: S = k In W |
Lecture 5 Play Video |
The Equipartition Theorem Recorded on April 11, 2012. Slide Information: 00:21 - Announcements 02:34 - Diagram: in real molecules, the situation is considerably more complex than the Harmonic Oscillator 03:20 - We have a very high density of translational states that are not, in reality... 03:36 - Diagram: these translational states are nested within rotational states 03:58 - Diagrams (many rotational states) 04:23 - ...we can treat each of these energetic manifolds... 05:45 - What's in this Lecture 05:51 - Your book mainly focuses attention on... 07:27 - Graph 5-13: Here is what happens to Cv as a function of T for a diatomic molecule: 10:04 - Graph 5-13 These are the rotation temperature... 11:08 - Graph 5-13 Here is what happens to Cv as a function of T... 11:37 - The Equipartition Theorum 12:10 - The Equipartition Theorum (with diagram) 13:17 - consider the classical Hamiltonian for a I D harmonic oscillator: 14:16 - now you'll recall that the heat capacity... 15:03 - Example: Formula 15:50 - Graph 16:13 - ...this is also the heat capacity for all monoatomic gases... 18:29 - For a linear molecule... 19:41 - Graph (Translation + Rotation) 20:26 - For a nonlinear molecule... 20:54 - What about for higher temperatures? 22:08 - so following through with the predictions of the equipartition theorem... 23:05 - so for a diatomic molecule... 24:24 - Example: Use the equipartition theorem to estimate... 31:18 - Example: Use the equipartition theorum to estimate... (Part B) 34:36 - Example: (Chart) "Use the equipartition theorum to estimate... (Part C) 38:55 - Calculate Each Term 39:18 - We'll Start with Translation... 39:40 - The translational energy of a classical gas molecule is: 40:15 - ...And a quantum mechanical gas has energies given by the particle-in-a-box model. 40:23 - we'll concentrate attention now on ideal monoatomic gases... 41:27 - consider first a monoatomic gas in one dimension. 43:59 - ...now these energies are very closely spaced. Consider, for example, an argon atom in a box... 45:25 - Log Scale 45:52 - ...if these states are quasi-continuous, we can rewrite this summation... 46:54 - so after integration we have... 47:05 - Example "Calculate..." 48:26 - What would...three dimensional cube? 49:36 - ...in terms of...now we calculate its transitional energy. 50:03 - ...and this yields a very simple expression |
Lecture 6 Play Video |
The Rotational Partition Function Recorded on April 13, 2012. Slide Information 00:05 - Introduction 00:19 - Announcements 01:10 - What's in this Lecture? 01:25 - Neglecting electronic energy levels... 01:41 - Vibration, Rotation, Translation Diagrams 02:19 - but we're lucky. We can treat each of these energetic manifolds separately... 02:51 - ...consider first a monoatomic gas in one dimension... 03:43 - ...so its molecular partition function, q, is: 04:29 - Diagram: Calculation of Ground State and Excited State 05:02 - Diagram: ...looking at the energy spacing of the first 100 states... 05:40 - ...If these states are quasi-continuous, we can rewrite this summation... 06:08 - Diagram: ...so after integration we have: 06:13 - Example: Calculate... 07:22 - Diagram: ...is related to the molecular properties through the mass... 08:28 - In terms of... 09:24 - Diagram: the enthalpy, H... 09:52 - Chart: so we can calculate everything for ideal, monoatomic gases... 11:10 - ...this begins to fulfill the promise of Statistical Mechanics: 11:41 - ...works for all ideal molecules. 11:51 - we have a manifold of rotational states that looks like this... 12:20 - ...and the energies of these states are given by the expression... 14:13 - ...B here has units of joules: 14:53 - ...I'm easily confused, so I try to stick to Joules: 15:26 - so let's work out the expression for... 16:01 - our usual expression for q applies for each of these three orthogonal axes: 16:27 - ...so if we write out this series, here's what it is: 18:36 - when B is expressed in Joules, these are the equations for the rotational partition function that apply: 19:43 - what's a symmetry number? 21:14 - huh? what axis? 21:59 - Ammonia 22:36 - Number of Symmetries: 26:55 - Example: Exercise 17.4a What is the symmetry of: 31:11 - Example: What is the symmetry number of: |
Lecture 7 Play Video |
Vibrational Partition Functions Recorded on April 16, 2013. Slide Information 00:05 - Introduction: Vibrational Partition Functions 00:17 - Quiz 2 Histogram 00:41 - The Symmetry Number 04:14 - We also get this answer using my approach. 07:09 - Aluminum Chloride Atoms Example 09:45 - We also get this answer using my approach (Diagram example) 13:03 - What is the symmetry number of: benzene? 15:43 - Estimate the rotational partition function for HCl... 16:09 - Linear molecules lacking a center of symmetry: 16:41 - Estimate the rotational...(formula) 19:12 - Calculate the rotational partition function for methane. 22:02 - Vibrational States 23:23 - ...including the zero point energy, we have... 24:52 - this geometric series has the form: 25:40 - how big is... 28:04 - Example: The triatomic molecule, chlorine dioxide (OCIO) has three vibrational modes... 31:42 - Graph: What Does the T-dependence...look like? 32:45 - Of course, molecular dissociation would occur before... 32:58 - thinking about the partition functions at room temperature, we conclude... 33:24 - What about vibrational energy? 35:13 - E=RT, Equipartition Theorum 36:13 - Here's a midterm exam question from a couple of years ago: 37:55 - Midterm exam solution 39:10 - Equations Page of Exam 41:03 - Calculations and Solution 41:40 - If you are asked: calculate the fractions of molecules for which... 42:25 - Calculations: ("now one mole of...) 44:47 - Example 45:07 - B. Now one mole of... 45:18 - Example (as in 44:47) |
Lecture 8 Play Video |
The First Law Recorded on April 18, 2012. 00:01 - Announcements 00:58 - Example: the triatomic molecule, chlorine dioxide... 04:27 - Plot of equation (Diagram) 09:40 - Thermodynamics 11:39 - Energy 14:24 - In Thermodynamics, we divide the universe into the system... 15:30 - Diagram: Now there are three flavors of systems: 17:32 - Glossary of Thermodynamic Jargon (Types of Equilibrium) 18:15 - We'll be talking about closed systems until further notice. 20:23 - now, we know what heat is, but what is work? 21:28 - let's think about mechanical work... 23:54 - the external force is: 25:57 - now what happens to the volume? 28:27 - Example: Calculate the work required to compress... 30:15 - Our equation for work... 31:45 - Answer: Graphically, this experiment is as shown below... 34:23 - So instead of compressing the piston using the entire mass necessary... 35:01 - Diagram: Step 1 35:18 - Step 2 36:22 - Conclusion: 36:24 - Diagram: so, more steps means less work. 36:52 - In the thermodynamics, a reversible process is any process the direction of which can be reversed by... 38:54 - Diagram: so instead of dividing the mass into two parts... 40:07 - ...add one granule at a time to the piston 40:50 - So as an example... 43:38 - Chart: Summary: 44:37 - Let me just point out that both of these equations conform... 45:47 - other flavors of work... 46:27 - that's w, what about q? |
Lecture 9 Play Video |
Law (review) & Adiabatic Processes Part II UCI Chem 131C Thermodynamics and Chemical Dynamics (Spring 2012) Lec 09. Thermodynamics and Chemical Dynamics -- The First Law (review) & Adiabatic Processes Part II -- View the complete course: http://ocw.uci.edu/courses/chem_131c_thermodynamics_and_chem... Instructor: Reginald Penner, Ph.D. License: Creative Commons BY-NC-SA Terms of Use: http://ocw.uci.edu/info. More courses at http://ocw.uci.edu Description: In Chemistry 131C, students will study how to calculate macroscopic chemical properties of systems. This course will build on the microscopic understanding (Chemical Physics) to reinforce and expand your understanding of the basic thermo-chemistry concepts from General Chemistry (Physical Chemistry.) We then go on to study how chemical reaction rates are measured and calculated from molecular properties. Topics covered include: Energy, entropy, and the thermodynamic potentials; Chemical equilibrium; and Chemical kinetics. Thermodynamics and Chemical Dynamics (Chem 131C) is part of OpenChem: http://ocw.uci.edu/openchem/ This video is part of a 27-lecture undergraduate-level course titled "Thermodynamics and Chemical Dynamics" taught at UC Irvine by Professor Reginald M. Penner. Recorded on April 23, 2012. 00:07 - In Today's Lecture 00:20 - heat, q, and work, w 00:51 - The Sign Convention 01:16 - Formula and Diagram ("surroundings") 03:19 - Diagram: (heat, q...) 04:11 - Other Flavors of Work: 04:30 - That's w, what about q? 05:27 - Since chemical reactions are typically carried out at a constant... 06:01 - Formula: it's convenient to give the quantities in parentheses a name... 06:33 - "Two forms of.." Calcite and Aragonite photo 06:55 - Problem: The change in U when 1.0 mole of calcite is... 09:43 - The heat capacity is the slope of the U (or H) 11:14 - Problem: a common method for measuring heat capacities... 13:31 - "Heat capacity over constant pressure..." (formulas and solutions) 14:16 - Problem: Find ΔH for the heating of 2.0000 moles... 16:47 - Adiabatic Processes 20:58 - Graph ("Isotherm...") 23:18 - Problem: 2.0 moles of neon that expands adiabatically... Required attribution: Penner, Reginald Thermodynamics and Chemical Dynamics 131C (UCI OpenCourseWare: University of California, Irvine), http://ocw.uci.edu/courses/chem_131c_thermodynamics_and_chem... [Access date]. License: Creative Commons Attribution-ShareAlike 3.0 United States License. (http://creativecommons.org/licenses/by-sa/3.0/us/deed.en_US). |
Lecture 10 Play Video |
Jim Joule Recorded on April 23, 2012. Index of Topics: 04:13 - In an adiabatic process, q=0 for the process... 07:51 - note: The change in P with an expansion is larger... 08:04 - Isotherm Graph 10:21 - ...now it's not obvious from these equations... 13:27 - About Jim Joule 14:20 - Joule's dad was a brewer 18:24 - Now, you should know that Joule was quite an experimentalist. 20:09 - Diagram: He actually did this experiment quantitatively 21:04 - The quantity of work that must be expended at sea-level... 22:35 - 77255 and California DMV 22:58 - Diagram: ...so in 1853, he did the following experiment 23:44 - So why did Joule expect a temperature change? 23:49 - ...this is the Leonard-Jones 6-12 potential. 27:29 - For an ideal gas, the intermolecular potential... 27:38 - Diagram: At high pressures, you're here. 28:17 - Diagram: At "normal" pressures, you're here. 28:43 - Well, recall that for a real gas, the compressibility factor... 29:09 - The compressibility factor, Z, for a real gas... 30:29 - The compressibility factor, Z, for a real gas reflects these two manifolds... 31:00 - (Diagram) Now, let's do a thought experiment... 32:33 - question: where does the energy come from? 34:03 - 1853: Jim Joule tried to measure... 35:05 - 1854: Joule teams up with a new friend, William Thompson (AKA Lord Kelvin) 36:40 - The Joule-Thompson Effect... 39:43 - so, the Joule-Thompson process occurs at constant enthalpy. 41:12 - but Joule and Thompson were delighted to find that for real gases... 41:52 - Problem: The Joule-Thompson coefficient of air at 300K and 25 atm... 45:13 - "Plot from your Chapter 14...temperature as a function of pressure." 45:54 - note that real gases have two inversion temperatures at each pressure value: 47:13 - The Linde Refrigerator: A mechanical heat pump... |
Lecture 11 Play Video |
Midterm I Review Recorded on April 25, 2012. 00:05 - Announcements 00:28 - Midterm Exam 00:52 - Partition Functions: Enjoy in any of Four Flavors... 01:51 - Example: The NO molecule has a doubly degenerate... 03:24 - Plot It: 05:01 - ...(b) the electronic contribution to the molar internal energy... 05:08 - Equations 05:22 - More Equations 05:38 - (Diagram) The electronic contribution to the molar internal energy... 06:32 - Here's a midterm exam question from a couple of years ago. 08:42 - Which equation(s) do I need? 10:31 - If you are asked: calculate the fraction of molecules... 10:48 - so what were we asked again? B. Now one mole of... 12:06 - The equipartition theorem: 13:33 - now you'll recall that the heat capacity... 14:15 - Formula: the equipartition theorem tells us... 14:17 - the equipartition theorem tells us that translation contributes... 14:41 - Graph: the contribution of molecular translation... 14:55 - Formula: ...this is also the heat capacity for all monoatomic gases 16:01 - For a linear molecule: 16:44 - Graph: translation + rotation 16:53 - For nonlinear molecule: 17:45 - ...well, let's go back to the classical Hamiltonian again. 18:12 - so following through with the predictions of the equipartition... 18:58 - Formula: in the specific case of a diatomic, we get: 19:02 - Formula Graph: 19:10 - Example: Use the equipartition theorem to estimate... 20:05 - Too subjective, let's use this rule of thumb: |
Lecture 12 Play Video |
Entropy and The Second Law Recorded on April 30, 2012. Slide Information 00:09 - Introduction 01:02 - Announcements 02:11 - where are we (chapter and timeline)? 04:00 - 1st Law: Energy is conserved for an isolated system ΔU = 0. 05:32 - Coin Experiment 06:35 - experiment: conclusion (the most important one so far) 06:51 - Boltzmann postulated that this parameter 07:11 - We can readily apply this equation to this expansion of gas. 08:11 - Now, what is the probability that... 09:05 - Problem: Gas A and Gas B are located in two halves of a container 13:07 - What if instead of the change in entropy... 13:33 - Formula (S =) 14:09 - Calculate the standard molar entropy of neon gas at (a) 200K, (b) 298.15K. 15:53 - Sadi Carnot 17:54 - match the scientist with his country 18:44 - entropy 19:28 - the Carnot Cycle 21:00 - A heat engine extracts work from a temperature gradient 21:41 - The Carnot Cycle (graph) 23:31 - what do we know for sure? (graph continued from Carnot Cycle) 24:18 - how efficient is a heat engine? 25:10 - efficiency (slide at 24:18 continued) 26:24 - how efficient is a Carnot Cycle? 27:28 - let's prove this: 27:52 - now, this pair of (T,V) data points lie on an adiabat: 29:55 - Problem: A heat pump is used to maintain the temperature of a building at 18°C... 32:03 - Problem: What is the entropy change, ΔS, for each of the four steps as a reversible Carnot cycle 32:31 - Diagram: Since S is a state function, we can write: 33:50 - so we represented in a Temperature-Entropy diagram... 34:48 - Since S is a state function, we can write: |
Lecture 13 Play Video |
The Carnot Cycle Recorded on May 2, 2012. Slide Information 00:06 - Introduction: The Carnot Cycle (Lecture 13) 01:02 - Announcements 02:39 - Midterm I Score 07:04 - How Am I Doing (Scores)? 09:37 - Sadi Carnot 10:52 - A heat engine extracts work from a temperature gradient. 11:38 - The Carnot Cycle 12:43 - The Carnot Cycle (Graph) 12:56 - ...ANY process can be decomposed into a large number of Carnot Cycles, so... 14:59 - how efficient is a heat engine? 16:12 - Let's prove this: 16:37 - (Graph) now, this pair of (T,V) data points lie on an adiabat: 20:27 - Problem: What is the entropy change... 21:05 - Since S is a state function, we can write: 24:07 - Formulas: What do we know? 25:55 - so (once again) represented in a Temperature-Entropy... 26:43 - What if one or more steps of the process are irreversible? 30:13 - Rudolf Clausius! 30:50 - T-shirt of Clausius 31:31 - and a more general statement of this is called the Clausius Inequality 31:59 - let's say we transition from state I to state 2... 33:02 - according to the Clausius inequality: 33:42 -The Second Law of Thermodynamics. 33:48 - This equation makes predictions about 3 types of processes: 34:30 - If we consider, in particular, an isolated system... 35:18 - some simple but important examples: 36:55 - some simple but important examples: (II) 39:53- Because S, like U, is a state function, you can add... 40:34 - example - Calculate the entropy change when Ar gas... |
Lecture 14 Play Video |
The Gibbs Energy Recorded on May 7, 2012. Slide Information 02:15 - Introduction (The Gibbs Energy) 03:30 - ...just one of these guys won Nobel Prize - which one? 07:14 - J. Willard Gibbs (1839 - 1903) 10:44 - ...has its own Facebook page 10:57 - buried in the Grove Street cemetery... 11:10 - Map "...Yale campus" 11:37 - Map II 12:10 - we now know some basic thermodynamics concepts and their statistical... 12:52 - Diagram: The system and the surroundings: Three flavors... 13:39 - Diagram: For an isolated system, the entropy of the system increases during a spontaneous process: 14:13 - Diagram: If the system isn't isolated, then the entropy of both the system... 15:03 - For an isolated system, the entropy of the system increases... 16:26 - (cont) q is a conserved quantity... 17:59 - now multiply by... 26:04 - but in chemistry, T is frequently constant... 28:02 - for any process occurring at const. volume... |
Lecture 15 Play Video |
Getting to Know The Gibbs Energy Recorded on May 7, 2012. Slide Information 00:06 - Introduction: Getting to know the Gibbs Energy 00:51 - Announcements: 01:54 - UC Irvine wins NCAA men's volleyball title... 02:19 - Today's tasks 02:42 - Diagram: The system and the surroundings: Three flavors... 04:22 - Formula (spontaneous process: nonisolated system) 04:43 - q is a conserved quantity... 06:09 - Chart: in Friday's lecture... 07:20 - in chemistry, T is frequently constant... 07:55 - let's consider... 09:57 - to achieve the const. volume condition... 11:16 - for any process occurring at const. volume and temperature... 11:50 - In chemistry, it is even more useful to be able to make predictions... 14:17 - for any process occurring at const. pressure... 14:37 - today (and, ahem, last Friday) 14:54 - Chart 15:56 - Graph ("reaction coordinate...") 19:10 - Among these four thermodynamic "potentials"... 20:37 - How does G depend on temperature? 21:00 - conclusions: 21:20 - plot (Gibbs energy and temperature) 22:04 - now, if we substitute from this equation for S... 22:31 - substitute and solve for the derivative 23:30 - now, to go further, note the chain rule that tells us that: 24:40 - (cont) this bad boy is called the Gibbs-Helmholtz Eq. 25:56 - Ok, now how does G depend on pressure... 27:35 - conclusion: Gibbs energies of solids and liquids... 28:18 - Gibbs energies of gases depend strongly on P. 29:20 - Diagram, Formula 30:19 - We define a standard molar Gibbs... 31:08 - Graph, Formula 32:54 - exercise 15, 29b: The change in the Gibbs energy of 25 g... 39:20 - exercise 15.24b: Calculate the standard Gibbs free energy change... |
Lecture 16 Play Video |
The Chemical Potential Recorded on May 9, 2012. Slide Information 00:05 - Announcements: 01:41 - Today: 02:40 - The Chemical Potential 02:50 - ...from last Monday, and last Friday: 03:48 - useful | more useful 04:49 - Graph (What does...) 06:28 - How does G depend on temperature? 08:28 - The third law of thermodynamics... 09:50 - Graph 10:32 - We usually consider the temp. dependence of... 11:26 - This bad boy is called the Gibbs-Helmholtz Eq. 12:09 - This bad boy...(cont) 12:43 - Ok, now how does G depend on pressure... 13:54 - but, for phases, like solids and liquids, that are essentially... 14:17 - For ideal gases: 14:47 - conclusion: Gibbs energies of solids and liquids... 15:40 - The T-dependence of the Gibbs function: 17:31 - Now, as we transition (however briefly) into... 18:06 - How do individual reactant and product species... 18:17 - Matter matters: How is G affected by transfers... 18:45 - we haven't said much about open systems that exchange matter: 18:54 - consider the mixing of two isotopes of hydrogen (experiment) 21:10 - since G is an extensive variable 22:09 - we understand the T and P dependencies of G already... 23:57 - we know, after we open the valve, the isotopes will... 26:06 - combining these statements allows us to express... 28:05 - so with the valve open, mixing stops when... 29:33 - The partial molar Gibbs free energy is to.. 33:34 - the partial molar Gibbs free energy (cont) 32:44 - The figure from your book really helps... 34:54 - the partial molar Gibbs free energy is too important 39:38 - exercise 16.4b: A mixture of ethanol and water is prepared... 42:34 - Now, we already understand that G is minimized upon an approach to equilibrium... 42:39 - In other words... 44:00 - This is called the Gibbs-Duhem Eq. 44:57 - Graph: This permits an understanding of thermal phase transactions: 45:36 - We already know how this works for, say, water: 49:13 - "the system "selects" the phase of lowest..." 49:24 - now, before we go further, let's clear up some mystery... |
Lecture 17 Play Video |
Finding Equilibrium Recorded on May 9, 2012. Slide Information 00:06 - Introduction Finding Equilibrium 00:21 - today: 00:58 - how do individual reactant and product... 01:22 - what can we deduce about the equilibrium state... 01:35 - we know, after we open the valve... 02:19 - so with the valve open, we showed that the mixing stops when: 03:35 - the chemical potential of species I. 04:47 - really? yes, think about it this way: 07:16 - you should know... 10:18 - Now, we already understand that G is minimized upon... 10:31 - now, before we go further, let's clear up a mystery... 11:25 - let's return to our two gas bulbs: 11:42 - ...let's return to... 12:02 - Diagram: ...we open the valve... 12:31 - Let's calculate G: 14:49 - hey, that's not on the line. 15:51 - now, since we know: ΔG = ΔH - TΔS... 16:38 - Graph 17:59 - resveratrol makes things live longer...what things? 18:22 - resveratrol makes things live longer...what things (photos) 18:46 - it also prevents cancer in mice... 19:20 - and resveratrol is found in red wine. 19:42 - does this have anything to do with thermodynamics? 20:19 - consider this generic isomerization reaction: 21:01 - Example 21:14 - now, our plot of G versus reaction coordinate... 21:46 - we define the slope of this plot at any value... 23:08 - so under conditions of const. P and... 24:58 - "that means there's three types of reactions..." 25:20 - It's a strange word, infrequently used even by chemists... 25:51 - Exergonic 25:57 - ok, but we still have not learned any more about WHERE equilibrium... 26:40 - we define a standard molar Gibbs free energy... 28:19 - ok, now for every value of... 29:45 - in other words... 30:00 - what does this mean? 31:23 - ...refresher on... |
Lecture 18 Play Video |
Equilibrium In Action Recorded on May 14, 2012. Slide Information 00:06 - Introduction - Equilibrium in Action 00:21 - Good job on Quiz 5 01:19 - Today 01:45 - the chemical potential of species... 02:34 - ...think about this way "...Gibbs energy" 03:33 - about μ, you should know... 04:44 - now, before we go further, let's clear up a mystery... 05:31 - Diagram 06:36 - Diagram: This is the positive entropy of mixing - the reason equilibrium exists. 07:39 - Consider this generic reaction ("extent of reaction...) 08:07 - For example, if ΔΕ... 08:30 - now, our plot of G versus reaction coordinate can be recast... 08:48 - we define the slope of this plot at any value of E... 09:47 - so under conditions of const. P and... 10:54: so as a function of E... 11:35 - ok, but we still have not learned any more about WHERE equilibrium is located... 12:43 - we define a standard molar Gibbs free energy... 13:41 - ok, now for every value... 15:10 - In other words... 15:45 - what does this mean? 16:17 - ok, make sense. What about... 17;36 - ...refresher on...("from Chem 1...") 18:54 - returning to our plot, we can say... 20:01 - example: A mixture of CO(g)... 21:41 - Diagram: our reaction looks like this... 24:10 - answer: 2) write an expression for... 24:39 - answer: 3) Calculate K: 25:29 - we know Q and K - what happens? 25:47 - Calculate 26:35 - ...means reaction, at this temperature and with this mix... 27:28 - example: What if, instead of... 28:26 - "we will make a little more methanol...by adding more..." 29:26 - example: Consider the following reaction... 36:48 - answer 39:58 - Henry Louis Le Chatelier (1850 - 1936) 40:19 - (cont) "I let the discovery of the ammonia synthesis slip through my hands..." 42:35 - the most influential persons of the 20th century? 44:17 - where did fixed nitrogen come from before 1920? 45:48 - Le Chatelier's Principle says, for example...that with an increase... 47:22 - Example: Can we determine the relationship between... 47:44 - answer: " we have to calculate the mole fraction of each of these two components..." |
Lecture 19 Play Video |
Observational Chemical Kinetics Recorded on May 16, 2012. 00:06 - Introduction: Observational chemical kinetics 00:17 - Henry Louis Chatelier (1850 - 1936) 00:25 - Henry Louis Le Chatelier..."I let the discovery of the ammonia sythesis slip..." 02:21 - Le Chatelier's Principle says, for example, that with an increase in the total... 02:47 - example: Can we determine the relationship between... 03:06 - answer: 06:30 - what about the influence of temperature on K? 08:12 - That's it for Thermodynamics (Topic discussed in Chapter 17) 10:11 - Diagram: where are we? 12:30 - the first chemical subjected to kinetic analysis? 13:12 - some notation & jargon...a stoichiometric reaction... 17:30 - so an elementary reaction is one in which the indicated products... 17:53 - we discussed the extent of reaction... 18:52 - this is not as confusing as it looks. Here's an example... 20:19 - in terms of the extent of reaction... 22:44 - ...for this generation reaction... 23:20 - in terms of the extent of reaction... 23:30 - A rate law relates the concentration of reactants... 28:23 - for stoichiometric reactions, the rate law can not be deduced by inspection. 30:08 - Often, reactions are significantly reversible and both the forward and backward... 32:10 - be reminded that these simple expressions apply only because... 33:35 - what are the units of the rate constant in this case? 34:46 - Method 1. Method of Initial Rates 40:05 - Method 2. Use an integrated rate law. 43:59 - Method 2. (continued) Half-life 45:17 - Graph: (length of half of line is constant.) 45:55 - How do we experimentally determine the rate of law |
Lecture 20 Play Video |
The Integrated Rate Law Recorded on May 18, 2012. Slide Information 00:09 - Introduction: Integrated Law 00:18 - today... 00:41 - Two types of reactions: take for example the following: 02:19 - stoichiometric 03:12 - for elementary reactions... 04:09 - this is another bimolecular reaction 07:14 - How do we experimentally determine the rate law? 17:48 - Method 3 - Use the integrated rate law to define the half-life of the reaction. 20:30 - vs time for a 2nd order reaction... 21:10 - Method 2: Use an integrated rate law. 21:56 - we've mentioned 1st order and 2nd order reactions...zero order reaction. 23:15 - [A] vs time for a 0 order reaction 23:56 - what kind of reaction does this? 24:36 - the microscopic view of "heterogeneous" catalysis 26:00 - some common integrated rate laws. 27:06 - so in reality, we have three methods for classifying a reaction... 28:30 - Method 3. Measuring the influence of initial reactant concentration... 29:08 - example: what % will decompose after one hour? 30:34 - For reversible reactions, we mentioned... 31:34 - Let's start with the simplest reversible reaction |
Lecture 21 Play Video |
The Steady State Approximation Recorded on May 21, 2012. Slide Information 00:05 - some announcements... 02:37 - today... 03:36 - Svante Arrhenius 04:20 - Arrhenius discovered the greenhouse effect in 1896 04:39 - Article Arrhenius wrote about climate change 05:59 - experimentally we often observe an acceleration...Arrhenius Equation. 10:25 - consecutive reactions are sequences of reactions... 11:49 - an understanding of consecutive reactions is important... 12:44 - consider this generic consecutive reaction: 14:28 - what do these equations predict about [B] versus time? 18:02 - Ok, now let's look at the other possibility: 18:36 - what if... 20:23 - this suggests an expedient method for dealing with...steady-state approximation 25:50 - So - how does this compare with the exact solution? 27:08 - ...Let's first examine a case where we expect that it will work well... 28:40 - now we'll make... 29:16 - now a case where we expect... 30:32 - ...and this is a complete disaster - just as expected. 31:16 - the Steady-State Approximation: 33:43 - REMEMBER: this works if... 33:58 - Irvine Langmuir 35:00 - a page from G.N. Lewis's lab notebook... 35:26 - Photo: How does this work (tungsten bulb)? 37:35 - until 1906, all lightbulbs had carbon filaments. These bulbs were also evacuated 42:20 - the Lindeman-Hinshelwood mechanism... 48:18 - let's apply the steady-state approximation... |
Lecture 22 Play Video |
Midterm Exam Review Slide Information 00:05 - some announcements 00:44 - Chem 131 C Quiz 6 03:23 - Youtube search for Chem Lectures 03:34 - chemistry lecture page with YouTube link 03:53 - what does Midterm Exam 2 cover? 04:46 - "what does Midterm Exam 2 cover?" 06:12 - Papers about La Chatellier Principle 06:52 - what was I thinking about? The ammonia synthesis reaction is: 08:10 - what was I thinking about? Iron is a catalyst for this reaction in the Haber-Bosch process... 13:38 - Problem I - entropy and the Carnot cycle (see especially Lecture 13) 14:13 - entropy - statistical definition: 14:32 - Diagram: now, there are three flavors of systems: 15:05 - The Carnot Cycle 15:16 - a heat engine extracts work from a temperature gradient. 15:37 - Graph: The Carnot Cycle 16:22 - Graph: ...ANY process can be decomposed into... 18:12 - Graph: What do we know for sure? 19:47 - how efficient is the heat engine? 20:21 - Diagram (work over heat) 20:39 - how efficient is a Carnot Cycle? 22:47 - Graph: ...now this pair... 23:49 - let's prove this... 24:03 - so the total work is: 24:51 - Problem: What is the entropy change... 25:08 - Since S is a state function we can write... 26:08 - so represented in a Temperature-Entropy diagram, a Carnot cycle looks like this... 26:33 - What if one or more steps of the process are irreversible? 27:37 - and a more general statement of this is called the Claussius Inequality 28:19 - This equation makes predictions about 3 types of processes: 28:41 - some simple but important examples: 29:18 - some simple but important examples: example - a reversible phase transition. 29:51 - example - reversible heating/cooling of a gas. 30:48 - rev. expansion/compression of a gas. 31:45 - Calculating entropy changes for reversible processes on ideal gases: 32:26 - because S is a state function... 33:20 - Because S, like U, is a state function, you can add up... 33:53 - Calculate the entropy change when... 36:47 - Problem 2 37:09 - chemical potential of species... 37:38 - really? yes, think about this way ("...partial derivative") 38:24 -...you should know... |
Lecture 23 Play Video |
Lindemann-Hinshelwood Part I Recorded on May 30, 2012 Slide Information 00:06- Lindemann-Hinshelwood 01:22- Announcements 3:19- Today: Steady-State Approximation, Lindemann-Hinshelwood Mechanism 03:46- The Steady-State Approximation 07:58- Graph: Concentration, Time 08:25- Solve the Simplified Equations that Result 09:37- How Does This Compare with the Exact Solution? 10:25- How Well the Steady State Works- Graph of Concentration, Time 11:18- The Steady-State Approximation is Breaking Down 12:30- Example: Apply the Steady-State Approximation to the Following Reaction Mechanism 18:06- Simplifying Further 21:26- Two Limiting Experimentally Observed Rate Laws 24:40- Most Elementary Reactions are Either Unimolecular or Biomolecular 25:44- Biomolecular Reactions Have an Obvious Mechanism in the Gas Phase 26:17- Transition State Graph 26:42- But How Does a Unimolecular Reaction Occur? 27:06- Unomolecular Reactions- Isomerization 27:31- Unimolecular Reacions- Decomposition Reactions 28:05- How Does this Happen? The Lindemann-Hinshelwood Mechanism Provides an Explanation 30:10- Applying the Steady-Sate Approximation to the Lindemann-Hinshelwood Mechanism 31:10- The Strong Collision Assumption 13:35- Can We Apply the Steady-State Approximation to the Mechanism? 34:14- What Does it Predict? 37:26- What Does This Mean Mechanistically? 38:04- The Kinetics of Pressure-Dependent Reactions 41:19- We Can Write the LH Rate in This Form 43:29- Does it Work? Plot 44:09- It Doesn't Work So Well 45:44- Reactions Where a Pre-Equilibrium is Established 47:45- Test the Lindemann-Hinshelwood Mechanism for the Isomerization of Cyclopropane 49:02- The Data is Not Convincing- Plot 50:18- Use the Steady State Approximation Again |
Lecture 24 Play Video |
Lindemann-Hinshelwood Part II Recorded on June 1, 2012 Slide Information 00:06- Enzymes 00:14- Midterm II Results 01:12- How Am I Doing? 06:36- Today: Lindemann-Hinshelwood Mechanism, Enzyme Kinetics 07:58- Most Elementary Reactions are Either Unimolecular or Biomolecular 09:45- The Lindmann-Hinshelwood Mechanism Provides an Explanation 11:22- Can We Apply the Steady-State Approximation to this Mechanism? 12:52- What Does it Predict? 14:28- What Does This Mean Mechanistically? 16:20- Let's Apply the Steady-State Approximation 16:53- The Kinetics of Pressure-Dependent Reactions 20:08- If the LH Mechanism is Operating...Plot 20:45- Plot: Does it Work? 21:16- LH Mechanism: A Mechanism for Which a Pre-Equilibrium is Established 22:03- The Reaction Will Have an Apparent Second Order 22:34- Apply Mathematics to the Enzyme 24:42- Schematic Illustration of Enzyme Kinetics 26:35- Kinetic Scheme/Steady State Approximation Applied 28:52- Solving for [(ES)] 30:05- Obtaining the Michaelis -Menten Equation |
Lecture 25 Play Video |
Enzymes Pt. II Recorded on June 4, 2012. Slide Information 00:06- Enzymes (Second & Final Attempt) 00:45- Announcements 02:42- Chem 1 Students... 04:47- Today: Enzyme Kinetics, Enzyme Inhibition 5:00- How Enzymes Catalyze Reactions 07:27- Equations Specific to Enzyme Catalysis, Rate of Reaction 12:36- The Michaelis-Menten Equation 13:04- Simplifying the Rate of Reaction 15:20- Making the Michaelis-Menten Equation Useful 15:46- What's Happening if K2 is big? 16:56- If K2 is Big, if [S] is Big 17:56- And if [S] is Big, Then... 19:49- IF [S] is Small 20:27- Plot of Reaction Rate vs. Concentration of S 23:57- K2=Kcat=Turnover Number 24:30- Ratio Between V and Vmax 25:34- Basis for the Lineweaver-Burk Plot 27:15- The Lineweaver-Burk Plot 28:30- Problem From Last Year's Final Exam 31:28- What Could Possibly Happen to Mess This Up? 32:56- Classifying Inhibitors Based Upon Their Effect on the Lineweaver-Burk Plot 34:46- Three Flavors of Enzyme Inhibition: Competitive Inhibition 35:10- Out Competing a Competitive Inhibitor: Plot 37:10- What Influence Does Vmax Have on the Lineweaver-Burk Plot? 37:57- Noncompetitive Inhibition 39:28- Uncompetitive Inhibition 40:26- Derive the Math For the Plots 43:13- No Inhibitor/Inhibitor Equations 44:07- Table of Inhibition 45:18- The Classical Case of Competitive Inhibition: Malonate and SD 46:09- Succinate 46:15- Fumarate 46:36- Competitive Inhibitors Generally Resemble the Substrate of the Protein to which They Bind |
Lecture 26 Play Video |
Transition State Theory Recorded June 6, 2012. Slide Information 00:06- Transition State Theory 00:13- Announcements 01:24- Where Are We? 02:54- Where Does the Arrhenius Equation Come From? 03:54- Joke 04:34- Transition State Theory, Introduction 05:08- History of the Transition State Theory 06:54- Transition Sate Theory For a Gaseous Biomolecular Reaction 09:00- Notation applied to TST 11:16- Activated Complex 11:52- Working Out The Reaction Rate 14:30- Flashback to Ch. 17: Calculating Equilibrium Constants from Partition Functions 16:08- Difference Between Zero-Point Energies 16:34- Gibbs Free Energy as a Function of Reaction Coordinate 18:13- Generic Equilibrium applied to TST 19:15- TST Equilibrium 20:37- Frequency 21:17- Setting Two Expressions for the Reaction Rate Equal to One Another 23:25- Calculating the Partition Function for the Transition State 25:50- What is the Partition Function for AB++? 26:28- Vibration Along the Reaction Coordinate 27:24- Super Soft Mode 29:26- Partition Function 30:54- Rewriting K++ 32:06- The Eyring Equation 35:38- Calculating the Pre-Exponential Factor in the Arrhenius Equation 36:17- Applying to a Reaction that Occurs in Water 39:27- Equilibrium Constants in Solutions are Defined in Terms of Activities 40:26- Debye-Huckel Limiting Law 41:11- What D-H Predicts 42:02- Thermodynamic Equilibrium Constant 42:31- Comparing K and K' 44:31- Question: Adding NaCl to a Solution of Acetic Acid 46:32- Applying this Logic to TST 47:25- Equation for the Kinetic Salt Effect 48:00- What Does it Mean? |
Lecture 27 Play Video |
The Final Exam Recorded on June 12, 2012. Slide Information: 00:22- The Final Exam 05:36- TST For Ionic Reactions in Solution 07:26- How does the Ionic Content of a Solution Influence the Reaction Rate when Reactants are Charged? 08:52- How Equilibrium is Influenced by Ions in Solution and the Debye-Huckel Limiting law 11:06- Graphing what the Debye-Huckel Limiting Law Predicts 13:00- What We Want to Know About the Plot of the Graph 14:40- How the Equilibrium Constant is Affected by the Ionic Strength 15:33- The Thermodynamic Equilibrium Constant and the Concentration Equilibrium Constant 16:40- Comparing The Thermodynamic Equilibrium Constant and the Concentration Equilibrium Constant 18:28- Question: Adding NaCl to a Solution of Acetic Acid 21:46- Question: Solubility of the Above Problem 24:58- Why Does This Happen? Oppositely Charge Ions Attract... 25:37- Freely Arranging Ions In Order to Lower Their Energy 27:58- Favoring the Most Ionic State of the System 28:23- Applying this Logic to the TST Treatment of the Reaction 29:52- Equations at Infinite Dilution 30:36- Master Equation for Transition State Theory and What it Predicts 31:02- Plotting What is Predicted 34:05- The 131C Final Exam 35:57- Review Problem: Calculating The Michaelis Constant, Km, Vmax, Turnover Number, Catalytic Efficiency of an Enzyme 36:33- In Enzyme Kinetics, This is the Mechanism that Operates 37:32- Michaeilis-Menten Kinetics Graph: Reaction Rate/Substrate Concentration 38:24- The Lineweaver-Burk Plot 39:19- What Your Plot Should Look Like Qualitatively 40:11- Example Problem: Chemical Kinetics: Steady State Reaction 46:18- More Kinetic Issues- Rules for Reaction Rate 47:06- Method 1 for Experimentally Determining the Rate Law 48:25- Method 2 for Experimentally Determining the Rate Law 48:41- Example of Method 2 49:00- Method 3: Measuring the Influence of the Initial Reactant Concentration of the Reaction Half-Life 49:36- Summary of Three Methods 49:39- The Arrhenius Equation |
