Chem 104 1st Edition Lecture 21Current LectureOverview 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 AAdd B Consume B Remove A Produce ARemove B Produce BDecrease volume (by compression) Reduce molesIncrease volume (by expansion) Increase molesIncrease temperature Consume heat Decrease temperature Produce heat Increase pressure (by additionof an inert gas) No change in partial pressures No shift Add catalyst Both forward and reverse reactions speed up No shift Application of Le Chatelier’s PrincipleThese 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; kc = 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 reversedKreverse = 1/kforward - If we add 2 chemical equations If equation 1 + equation 2 = overall equation, then k = k1k2- Different ways to balance equations If we multiply equation by n, then k2 =
View Full Document
Unlocking...