AS CHEMISTRY QUERY - EQUILIBRIUM CONSTANT

[rackmeup]

Guys, could anyone explain to me that why only temperature changes affect EC while changes in concentration, pressure do not?
Shouldn't them all have effects on the position of equilibrium?? Many Thanks!!

By the way, hows everybody's revision going?? I ll be sitting mine next Monday, I am nervouse as hell :Z

[girl_92]

there is somethin such  as le chateliers principle according to it wen u increase the concentration the system will try to deacrease it by shifting to the othr side so does it do for pressure  changes in presssure actually attributes to changes in volume  and the constant is not affected by the total but partial pressure ( overall the total pressure stays constant) wen you increase the concteration of one substance system decreases it but overall the kc ratio will remain the same only wheareas at diff temp the value can chnage suppose hydrogen iodide at high temperstures it will decompose  more

hope u get it
if not ask me again 

[rackmeup]

there is somethin such  as le chateliers principle according to it wen u increase the concentration the system will try to deacrease it by shifting to the othr side so does it do for pressure  changes in presssure actually attributes to changes in volume  and the constant is not affected by the total but partial pressure ( overall the total pressure stays constant) wen you increase the concteration of one substance system decreases it but overall the kc ratio will remain the same only wheareas at diff temp the value can chnage suppose hydrogen iodide at high temperstures it will decompose  more

hope u get it
if not ask me again 

Thank u very much. Its all abt the math, isnt it?
sry to bother u again, bt do u know why weak acids and bases have smaller value of enthalpy change of neutralisation compared to strong acids and bases.
Dont the weak acids dissociate to ions(H+, OH-)completely if left there long enough? or if given sufficient amount of energy they will ionise as well.
If that extra energy is given, I figure that is some sort of activation energy, and the change in energy level between reactants and products is independent from the extra energy added.
I am confused
MANY THANKS

[CHEMMASTER6000]

not exactly , both strong and weak acid and base does infact dissociate completely given enough energy thus the dissociation is proportional to tempreture . how ever for a weak acid  to dissociate completely it has to attain energy thus its and endothermic reaction , thus the products of a weak acid is thermodinamically less stable then that of the reactants or at a higher energy level . however when we consider entalphy change of neutralisatoin we consider only 25 degrees tempreture or 298 k this at that specific tempreture the weak acid or base can only dissociate partially thus entalphy change is smaller . p.s all this extra stuff is in a2 though 

[rackmeup]

not exactly , both strong and weak acid and base does infact dissociate completely given enough energy thus the dissociation is proportional to tempreture . how ever for a weak acid  to dissociate completely it has to attain energy thus its and endothermic reaction , thus the products of a weak acid is thermodinamically less stable then that of the reactants or at a higher energy level . however when we consider entalphy change of neutralisatoin we consider only 25 degrees tempreture or 298 k this at that specific tempreture the weak acid or base can only dissociate partially thus entalphy change is smaller . p.s all this extra stuff is in a2 though 

THANK YOU INVERSE TANGENT GRAPH (I WONDER HOW IT LOOKS  LIKE)=)
THE SYLLABUS SAYS ITS AS THOUGH
GD LUCK WITH UR EXAM!!!

[CHEMMASTER6000]

hahaha no worries, youll do inverse tangent graph sooner or later. hahaah  good luck with yours too

[girl_92]

Thank u very much. Its all abt the math, isnt it?
sry to bother u again, bt do u know why weak acids and bases have smaller value of enthalpy change of neutralisation compared to strong acids and bases.
Dont the weak acids dissociate to ions(H+, OH-)completely if left there long enough? or if given sufficient amount of energy they will ionise as well.
If that extra energy is given, I figure that is some sort of activation energy, and the change in energy level between reactants and products is independent from the extra energy added.
I am confused
MANY THANKS

its perfectly alrytt i find ur questions sensible and very similar to those i ask in class so u can post more

yea as inverse tangent said enthalpy of neutralization is smaller because energy has to be invested in ionization of the acid or base but then im not really sure abt this but the diff is quite negligible