CHEM 1125Q 1st Edition Lecture 13 Outline of Last Lecture Ch. 13I. Osmotic Pressure, Electrolyte Solutions, Van’t Hoff Factor, Percent Dissociation, ColloidsOutline of Current Lecture Ch. 14II.Spontaneous ProcessIII. EntropyA. QualitativeB. MotionC. QuantitativeD. Change in EntropyCurrent LectureII. Spontaneous ProcessA. Spontaneous Processa. A spontaneous process is one that does occur under a specific set of conditions. For example, a boulder rolling downhill his spontaneous, while a person pushing it up is notb. The reverse process of a spontaneous process is not spontaneousc. Processes that result in an energy decrease in the system are almost always spontaneousd. Enthalpy alone is not enough to predict a system’s spontaneity III. EntropyA. Qualitativea. A system’s entropy (S) is the measure of disorder in that system, or how spread out that system’s energy isb. Both enthalpy and entropy must be known in order to predict spontaneityc. Entropy increases as volume increasesB. Motiona. Molecules have many different types of movement:i. Movement from one place to anotherii. Vibrationaliii. Rotational; an example is microwaves, which cause water molecules to rotateiv. Electronic; when electrons move orbitalC. QuantitativeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. As entropy increases, a system is more likely to be spontaneousi. S = k ln(W)S = entropyW = number of possible arrangements = XN X = number of cells in a volumeN = number of moleculesk = Boltzmann constant = 1.38x10-23 J/KD. Change in Entropya. The change in entropy is the difference between a system’s final and initial entropiesi. ΔSsystem = Sfinal – Sinitialii. ΔSsystem = nR ln(Vfinal/Vinitial)n = molesR = 8.31 J/mol
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