CHM 104 1st Edition Lecture 11 Outline of Last Lecture I Q versus K II Value of Q Outline of Current Lecture III Heterogeneous Equilibrium Calculations IV Le Chateliers principle Current Lecture Heterogeneous equilibrium calculations H2 g S s H2S g Sulfur is NOT involved in determining the EQ pressures of H2 and H2S BUT some of it will get USED H2 g I 0 200 C x E S s Used 0 200 x H2S g Kp 1 0 0 100 Q K x 0 100 x 15g CaO and 15g CaCO3 placed in container 1L 300 K What is the pressure of CO2 K p 92 6 CaO s CO2 g I 0 C x E x CaCO3 s The La Chatelier 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 If an influence disrupts an equilibrium the reaction will respond by moving in a way that partially counteracts the disturbance and restores Equilibrium Powerful Predictive Tool Example N2O4 g Kp 4 65 x 10 3 2NO2 g 0 570 atm 0 517 atm What if NO2 is suddenly pumped into the container so that the new pressure of NO2 is 0 200 atm N2O4 g 2NO2 g 0 570 atm Not at Equilibrium 0 200 atm Q K The reaction RESPONDS to the sudden increase in NO2 by using SOME to restore Equilibrium What if NO2 is suddenly removed from the container so that the new pressure of NO2 is 0 0400 atm N2O4 g 2NO2 g 0 570 atm 0 0400 atm Not at Equilibrium Kp 4 65 x 10 3 Q K Disturbance Response Add Product Use Product Remove Product Generate Product EQ Shifts Suddenly increase Pressure decrease volume Response system will try to lower pressure Pressure is proportional to moles of gas of NO2 combines to form more N2O4 there will be fewer gas molecules in the container If we increase temperature add heat energy how does that shift equilibrium DEPENDS on whether rxn is EXO or ENDO thermic N2O4 g 2NO2 g Endothermic needs heat Heat N2O4 g Add Heat 2NO2 g Response Use Heat If this had been an exothermic reaction then the reaction would shift to get back to equilibrium
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