the world’s most famous last words in any language: “hey, watch this.”

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THE WORLDS MOST FAMOUS LAST WORDS IN ANY LANGUAGE: HEY, WATCH THIS. Slide 2 LE CHATELIERS PRINCIPLE: IF A SYSTEM AT EQUILIBRIUM IS DISTURBED BY A CHANGE IN TEMPERATURE, PRESSURE, OR THE CONCENTRATION OF ONE OF THE COMPONENTS, THE SYSTEM WILL SHIFT ITS EQUILIBRIUM POSTION SO AS TO COUNTERACT THE EFFECT OF THE DISTURBANCE. KEEP IN MIND THAT A SYSTEM IN EQUILIBRIUM IS IN A DYAMIC STATE THE FORWARD AND REVERSE REACTIONS ARE EQUAL. THE SYSTEM IS IN BALANCE. IF WE ALTER THE CONDITIONS AS STATED ABOVE, WE UPSET THAT BALANCE. SO, THE SYSTEM IS GOING TO SHIFT TO A NEW STATE OF BALANCE A NEW EQUILIBRIUM. CONSIDER THE FOLLOWING REACTION: N 2 (g) + 3H 2 (g) == 2NH 3 (g) Slide 3 K eq = [NH 3 ] 2 / [N 2 ][H 2 ] 3 = [p NH3 ] 2 / [p N2 ][p H2 ] 3 IF WE ADD NITROGEN, THE SYSTEM IS GOING TO SHIFT TO REDUCE THE INCREASED CONCENTRATION OF NITROGEN, SO IT WILL SHIFT TO THE RIGHT. A SIMILAR SITUATION WOULD OCCUR IF WE INCREASED THE CONCENTRATION OF HYDROGEN THE EQUILIBRIUM WOULD SHIFT TO THE RIGHT. YOU CAN THINK IN TERMS OF THE EQUILIBRIUM CONSTANT. IF WE INCREASE A CONCENTRATION TERM IN THE DENOMINATOR, FOR THE K eq TO REMAIN CONSTANT, THE CONCENTRATION TERM IN THE NUMERATOR WOULD HAVE TO INCREASE. Slide 4 N 2 (g) + 3H 2 (g) == 2NH 3 (g) IN TURN, IF WE INCREASE THE CONCENTRATION OF AMMONIA, NH 3, THE REACTION WILL SHIFT TO THE LEFT TO COME BACK INTO EQUILIBRIUM. AT A GIVEN TEMPERATURE, THE EQUILIBRIUM CONSTANT IS JUST THAT CONSTANT. THE HABER PROCESS IS USED TO PRODUCE AMMONIA FOR USE IN FERTILIZER OR IN EXPLOSIVES. ONE WAY TO INCREASE THE PRODUCTION OF AMMONIA WOULD BE TO REMOVE IT FROM THE PROCESS AS IT IS PRODUCED. THIS CAN BE DONE BY LIQUEFYING IT. BP NH 3 = -33 o C BP N 2 = -196 o C BP H 2 = -253 o C Slide 5 EFFECT OF CHANGING THE PRESSURE AND VOLUME AGAIN, LETS CONSIDER THE SAME REACTION N 2 (g) + 3H 2 (g) == 2NH 3 (g) AT CONSTANT TEMPERATURE, WHAT HAPPENS IF WE INCREASE THE PRESSURE BY REDUCING THE VOLUME? IN THE ABOVE REACTION, WE HAVE 4 MOLES ON THE LEFT AND 2 MOLES ON THE RIGHT. IF WE INCREASE THE PRESSURE, THE REACTION WILL SHIFT IN A DIRECTION THAT REDUCES THE NUMBER OF MOLES OF GASES (REDUCES THE PRESSURE). SO, THE REACTION WOULD SHIFT TO THE RIGHT. INCREASING THE PRESSURE DOES NOT CHANGE K eq. IT CHANGES THE PARTIAL PRESSURES OF THE GASEOUS SUBSTANCES. Slide 6 ANOTHER WAY OF CONSIDERING DIRECTIONS OF REACTION IS TO TAKE THE ACTUAL CONCENTRATIONS AND CALCULATE A REACTION QUOTIENT AND COMPARE THAT TO THE EQUILIBRIUM CONSTANT. WHEN WE SUBSTITUTE ACTUAL CONCENTRATIONS INTO THE EQUILIBRIUM CONSTANT EXPRESSION, THE RESULT IS THE REACTION QUOTIENT. AT EQUILIBRIUM, Q = K eq. IF Q>K eq, THE REACTION WILL SHIFT TO THE LEFT. IF Q