Chem 104 1st Edition Lecture 21 Current Lecture Overview of types of changes involving Le Chatelier s Principle 2A g B g change in H 0 exothermic Type of stress Effect Direction of shift Add A Consume A Add B Consume B Remove A Produce A Remove B Produce B Decrease volume by Reduce moles Increase moles Increase temperature Consume heat Decrease temperature Produce heat Increase pressure by addition No change in partial pressures No shift Both forward and reverse No shift compression Increase volume by expansion of an inert gas Add catalyst reactions speed up Application of Le Chatelier s Principle These 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 Ammonia synthesis the Haber Bosch process N2 g 3H2 g 2NH3 g Change in H 92 2 kJ mol Kc 3 5 108 at 25C Problem very slow reaction have to break nitrogen nitrogen triple bond which leads to a very high activation energy Solution o Add catalyst o Increase temperature would shift equilibrium to the left k c 0 16 at 450C o Increase pressure roughly 200 atm o NH3 gas is converted into liquid and removed from system Manipulating k If reaction is reversed Kreverse 1 kforward If we add 2 chemical equations If equation 1 equation 2 overall equation then k k 1k2 Different ways to balance equations If we multiply equation by n then k2 k1 n
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