University:
California State University, Northridge
Course:
CHEM 100 | Principles of Chemistry
Academic year:

2023
Views:

369

Pages:

10
Author:

ronidalbo298 Roniwahyudi

Spontaneous Change, Entropy + Gibbs energy Spontaneous Process occurs naturally without any Outside help Noll- spontaneous process will not occaer with an external Source of energy *A Process which is Spontaneous in one direction is non-spontaneous in the other direction. *Spontaneous Processes proceed to equilibrium An external Example Spontaneous; ama (s) + (colano CCS) Ar H²-aky Non-Spontaneous; diMac (s) 2 Na (sc) + (₂(9) ATH²=22kJ/m Establishing criteria for spontaneous charge H2° (e) H2(g) AHVGP: 49 KJ/Thac (25,1 Nocils, Nat caq) +Cl^caap ATH°= 3.9 kJ/mol (25°C, llbar) 2 N2°5(3)-7 2.NO₂ (g) + 1/½ (9) ArH=1lok)/mol(25811 * A molecule has 3N types of random motion Called modes; N=#otoms (3 Translational modes? Linear molecules 2 rotational moves; 3N-5 Non-Linear 3 rotational modes; 31-6 Example; H₂o molecules. Translational; 411 atorno in one directions. together (can move in X,Y, 2 directions) Berlding Motion A HH HH +symetric Stretch HH HH Vibrational; H H Streten Solid State Moleceules can only vibrate about their equili Urkm Fositiono H→ H Rotational; *Also 2 axis symetric The liquid State Molecules can move Graund each other (translation) d have limited amount of rotational & Vibrational move ment. The gascous State Molecules have virtually unrestricted translational, rotational & vibrational movement Statistical Entropy - An interpretation of entropy at the molecular level - A measure of the degree to which thermal energy is dispersat in available energy levels associated with random molecolar Matton *Entropy is a State function; Changes is entropy ak pathiway Independ Entropy d. Available Quantized Energy levels molecullo Populate a greata # of energy levels Lenorgy IS more Spread out) when the energy gap AE between adjacent energy levels is small. This results ingreater entropy For the sample of molecules AF frinslational Gx10-198/mol (Approximak Valves AE rotational = GS/Mol AF Vibrational = 6000 S/mol AE Vibrational 1000 A Erotational >>>> DE translational cat any given inotant In time *Energy is mainly dispersed into translational d rotational energy levels where the energy gaps are extremely small. *Most molecules at a soc are in the lewest. energy Vibrational level of each of its Vibrational modes. Fairly high temperatures are needed to give molecules enough energy to give Populate higher energy Vibrational energy levels. Single Particle Nicrostate Any Particular energy State For a Single niolecule that describes that molecule at a given Instant in time. It is a Combination of its quantized translational, rotational, & Vibrational energy levels. N-Particle Microstate Any quantized State of a whde system of molecules. consists Of the collection of the Single Particle mirrostutes ofallits maecules Statistical EntPopy+ the HoF N-particle Nierostates 1. At anly given instant in time, the total energy of the system is dispersed throughout a single M-Particle microstate 2. in the next ilstunt in time, the total energy of the system is disperged t hroughout adifferent N-Particle microstate of equal energy 3. Each accessible N-Particle miscrostate is equally passible for the System.

Spontaneus Cange Entropy

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