Lec. 17. Equilibrium Calculations

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Lec. 17. Equilibrium Calculations
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UCI Chem 1B General Chemistry (Spring 2012) Lec 17. General Chemistry Intermolecular Forces -- Equilibrium Calculations -- Instructor: A.J. Shaka. Ph.D. Description: UCI Chem 1B is the second quarter of General Chemistry and covers the following topics: properties of gases, liquids, solids; changes of state; properties of solutions; stoichiometry; thermochemistry; and thermodynamics.
Setzen <Verfahrenstechnik> Pilot experiment Metabolite Phase (waves) Reaction mechanism Cell growth Battery (electricity) Growth medium Nutrient Food Wine tasting descriptors Systemic therapy Connective tissue Enzyme Rapid Protein Cobaltoxide ISO-Komplex-Heilweise Periodate Body weight Biochemistry
Molecule Stickstoffdioxid Electron Heterodimere Concentrate Human body temperature Containment building Electron Chemical reaction Pressure Electronic cigarette Catalytic converter
Area Molecule Ionenbindung Connective tissue Beverage can Concentrate Chemical property Molecule Molekulardynamik Erdrutsch Stuffing Chemistry
Ionenbindung Stickstoffatom Heterodimere Containment building Diamond Stickstoffatom Fed-batch-Verfahren Wursthülle Pressure Molecule Water Hydrogen Electron Human body temperature Molecule Cobaltoxide Carbon dioxide Cobaltoxide
Ionenbindung Nitrous oxide Species Stickstoffatom Weakness Valence (chemistry) Resonance (chemistry) Molekulardynamik Chemical bond Man page Lewisite CHARGE syndrome Valenzelektron Acid Electron Functional group Chemical structure Chemical structure Horse meat Mixture Cobaltoxide
Molecule Gas Chemical bond Gas Molecule Chemical reaction Chemistry Atomic number Atom Chemical reaction
Reaction rate constant Isomer Octane rating Concentrate Isomer Watt Chemical reaction Wursthülle Butene Chemical reaction
Reaction rate constant Match Octane rating Concentrate Mortality rate Operon Man page Wursthülle Chemical reaction Chemistry
Reaction rate constant Reaktionsgleichung Cell (biology) Glasses Molecule Steel Chemical plant Butcher Wear Lambic Electronic cigarette
the inactive neurons parked far too by your immune system for the complete destruction this is just not variation on the theme of use it or lose it the Kevin around just sitting around not going anyway they eventually get packed with protein and that growth mean that of them I probably also sells to get rid of that state it's not doing anything and then you lose that 1 and all connection and that could be of physical mechanism for why even somebody who is extremely good a musical instrument and doesn't do it for years to come back and they feel very rusty I think they can play with the same rapidity and style over that they had because when they stopped practicing in those neurons become idle your bodies as well look at all this metabolic globally that year 15 watts steaming out of his goal and this guy here is taking energy and food and oxygen and nutrients and Bob Loblaw and not doing anything we can prove yet fired in years gone it's true and perhaps 1 that mechanism goes astray or goes out of whack when you get older you're immune system starts getting rid of even parts of your brain that you would prefer to he and then he suffered but in the law and the 2nd fears of dual then the observation that Europeans are putting on weight well as long as violence prices rise as they become more like driving around the world and the interesting connection here Is that you I like the 3 if you sit down this morning and it's over you're on battery power you're Tennessee Texas 20 minutes of your own title and shuts down because why should it be metabolites and that and be ready to run and do things when you are doing it this is a self-defense mechanisms so so that you don't run out of energy however the set down for extended periods and then you eat the pilot on your biochemistry can't believe how and how fortunate things are guess what unlike King of France I'm sitting down and doing nothing and I'm getting food pandered to that never occurred naturally you had a climate treaty get some sour apple you had to chase something down you had at least right after the bugs you reading because we plenty of them they were much safer to eat them big animals to the big animal my interview with its great based on and if you got injured he would often die of infections if you know that you can explain why people to work every day on the treadmill which I would recommend that all are still here in there then what happened on the way out 3 other galleries something the 3 miles down to like did you do 3 miles of the formation of then and so on and and then let nature do its work the defeat that interesting you don't have to be an avid exerciser but just don't sit down for longer than 1 minute always get out through the media your full-year assessment of the school the people of that oxidizing enzyme going and you did In a new Wave much more effortlessly than by making a big push being tired and then the rest of the day you sit around when you are keeping track if you hadn't gone to the gym you will walk around a lot more and so you actually defeat yourself because you pay attention to this big bang like the payoff invaders I'm on the treadmill I'm doing and then the rest of the day when did not you don't even pay attention you say Well I'm tired but I want to sit down and I'm hungry so I want to eat and then you go backward OK let's go on now and talk about the equilibrium if
1st of all equilibrium is dynamic we talk about that last time nitrogen dioxide is the brown haze over Los Angeles it's a lot of it comes from cars it was much much worse before the days of catalytic converters which attempt to remove and all from the exhaust and it has an odd number of electrons which makes it very reactive in it and I'm arise the make and 204 which is colorless and if we have a ball and then to we have forward reaction judges decided to put an an end to all forests reacted and it falls apart into 2 N 2 the reverse and then of these sometimes recombine and at a certain temperature and pressure there were there will be an equilibrium concentration of these 2 different molecules In this complaint and we know by now that if we press on the container if we shrink like police pressure on that we will favor the reactant because the reactants since less moles of gas coming if we heeded the gets hot in the afternoon then we will savor them will get much more of that coming up smog
of course is much more than just an note to the whole which is stuff that has to do with photo chemistry and that's why it's much worse in the afternoon and that's why the time around slide because that's when the area is the best In all the idiots driving their cars should not there's still shaken off the the nite before so you much safer when you cross the the road as well because you won't have some I guess some people have actually been there on the sidewalk by someone in a car because the fiddling around doing something else and they jumped the curb and smashed into you that's really unfortunate but it does happen well I suppose we looked at this ball and wait tax we make an imaginary tab we put a tag on 1 piano to molecule we follow that the problem is this is very hard to do because molecules so tiny we can usually see but we can imagine and if we did that we'd find that part of the time it spends its time is to guest and part of the time it spends its time and 204 the hooked up with somebody else and the bonds are made and broken and remade all the time and in fact if we followed the percentage of
time but this diocese and all too often 204 find that was directly related to what the equilibrium concentration 1 but there is a connection between the time averages In averages of property and that study of so-called statistical mechanics is highly interesting things to engage in a more advanced let's have a look suppose then you don't believe it he said you told us you should rely on evidence what said is plausible but what's the editor but that actually happened How could we either confirm or rule it out
and the answer is we could do so by employing isotopes in this case stabilize we could use nitrogen 15 which is a nice Popov nitrogen rather than nitrogen for you it has pretty much the same bonding characteristics and everything else life working but it has not been the from and the news the electrons at pretty much the same and we could use oxygen 18 which they use and some medical procedures and we could make some molecules that have and 15 firstly make a batch of molecules and 15 and oxygen 16 abundant isotope and we make another bond there and for for me and in another container and we Mexicans an effective remits them we fly by for example now the problem is we fly that there isn't always keen and for me fuck 215 all 6 then we know that they rearrange that they randomly if on the other hand when we prepare this guy and we only find this guy and we only find that got in the next that's we find but we know that they say will but basically rearranged at all well maybe this experiment with curriculum molecule we find their installed In fact Florida the presence of the bomber and the diamond indicates that they have right otherwise we would have if you do this and experiment with carbon dioxide and prepare them carbon-dioxide with part of the Old City and parts while always clean and Mexico's normal temperature pressure there's no hint you never find antioxidant moving off 1 the other that you go to
extremely high temperature than you can ever have that feeling jury will bombs in actually rate and if you do the same thing with water In water find that the hydrogen around all the time if all of the commander of every which way but they're exchanging quite rapidly in liquid water OK let's have a look at the wider responded so we usually the
Lewis structure it is kind of a good way to start and look at the bomb and let stand right Lewis structures ran out 2 1 and 2 0 4 remember what we have to do we have to count the valence electrons we have to know how the are bonded because it's an ode to it's going to be and in the middle and oxygen sticking out like spokes and 2 0 which is nitrous oxide Pakistan then hand them both it's different let's do what's there is 5 valence electrons than I the 6 for oxygen but there's 2 oxygen and so I have 17 this is a very rare because whenever you have on the number of electrons that he's the 1 on parallel electrons some both United call the radical 20 usually cause mischief from the quietly and if you ever read any and all and I don't want say state you never forget it is a long time and say that's enough of that and you feel like you are in the public about depending how concentrated at was but don't try to clean up 10 in Niger grasses because it won't work you will produce enough to insist the pending will disappear so I tried to make an opt-out around its acidity oxygen and I can do that but in order to do it I have to have some minus charge on this oxygen because remember we count 1 electron for the ball then 1 2 3 4 4 5 6 so we count 7 electrons but oxygen screwed 6 this as a formal negative charge here we count 1 electron here once 2 3 4 5 6 this has no formal charge so we put nothing and the nitrogen Group 5 we count 1 to 3 but he's got a positive charge and that we can play the usual game of slipping this guy and flipping this guy out like playing dominoes and the negative charge moves back and forth the actual structure and too is 50 per cent the 1st and the include found that it's 1 structures but we can't write a proper Lewis structure for like that so with Lewis structures when we have more than 1 resident structure what we're saying is but the real guy a mule but you is not a proper species because it's a mixture of a horse and a donkey and so what we tried do to make it look like a mule is we flash of horse 50 per cent of the time and donkey 50 per cent of the time you we clash very fast in this kind of an average and that way we can draw proper Lewis structure for each 1 and this this is not meant to mean that this is literally happening this is just a man mean there's a percentage of each in the real structure which is an average which we don't want to drop his withdraw dotted lines and funny things we don't know where the electrons I think you can probably see that there's an electron here an electron here so I think you can guess how and 204 is made and I'll let you workout and 2 0 4 as not always ask you about it on Tuesday to see if there and I think you can see why it's a weak bond because when I make it I have to put those 2 formal positive charges together formal positive charges
paid each other and their close and so that bond is quite weak and means we can break apart fairly easily so the an normally weak chemical bonds that allows this to happen weekend take a
kinetic view of the equilibrium and I'm going to go through quite a lot of mathematics here just so you've seen it not that I want you to reproduce but so that you've seen it so when you see it again it'll be familiar the chemical reactions can only happen when atoms or molecules are close enough to make a bomb that basically means the molecules have the Colo the 1st happened yet and we can figure out how often things you get they have to collide and if we look at that hour kinetic theory of gasses we know How many years going how fast we can figure out how many times they did her 2nd in gas it is a very very very large number of hits that normal pressures we have kinetic theory of gasses and we can figure out I want but the atoms or molecules are going to collide and if we keep things up 2 things happen they're going to collide more often because everybody's going fast so it's as if time strong when they do collide more
often they're going to get harder as well so there is more chance that the hit so hard that some gets knocked off and then you get a reaction initiated so that's why most reaction speed up in both directions not just 1 but in both directions when we keep things up and will see this In the summer of you're going to continue on in this series and can 1 see With the Arrhenius equation OK let's have a look suppose
that we're summarizing since you the transmute for taking something like this and where I summarizing like that which means we have to to formally rated don't want momentarily slammed into it at this time will around and we know from before usually the transformed when you go through things sticking out slightly more favorable because when you like this these guys tend to repel each other a little bit and puts a little bit of extra energy there gets released Mommy go like that that doesn't mean it's easy to do what it can have if we had a forward rate constant which would call little case for forward of 5 . 5 9 times 10 to the minus 3 per 2nd and the reverse reaction has a slower rate constant a 4 . 4 1 times 10 to the minus 3 per 2nd and we began where the mall of assist Eugene and 1 flats what will be the concentration of the 2 isomers at equilibrium OK from the forward reaction runs at a rate that depends on product and but the rate constant and the concentration of says you says however many I've got this many Her seconded that tend to go this just like a conveyor belt that makes Transputer and then the Transputer reacts backward but at a slower rate more sluggish and that reverse reaction depletes Trans beauty then the 1 weapon
that we have in this time view of equilibrium Is there
at equilibrium whatever the amount of trans beauty has to be fixed because that's what equilibrium means the concentrations not changing and that means that the rate of gain plus the rate of loss must equal to 0 . 4 both the money in my bank account every month is saying that these might incomes and while I'm standing match that's the only way it can be the same let me say that again the only way it can be the same because is the amount you get and the amount you stand man if there even slightly off you eventually go into a black hole if on the other hand you have a slight surplus every month the unemployed up here and that's the correct way operators of course much less stressful now let's write the rate of gain the rate of gain depends on the forward plus how much says bewteen there'd equilibrium and the rate of loss depends on the reverse but it's negative I lost but I write the rate of loss being a negative number is minus whatever the rate of trans disappearing as times whatever the concentration is of equilibrium and if if it is an equilibrium that should be 0 and if I saw all this I find that the ratio of forward rate constant of the reverse rate constant is nothing other than the equilibrium concentration of France beating the product divided by the concentration of says beauty and that means I can get a number for social trends over says is forward which is 5 . 5 9 times 10 minus 3 divided by 4 . 4 1 times 10 minus chemistries go away and I get 1 . 2 7 the concentration of the products at equilibrium divided by the reactants in equilibrium that's that's not none other than and so we have a number 4 K 10 In this case is 1 . 2 7 not a very
favorable reaction but more favorable to make transparency this is the
general conclusion equilibrium by I had an abbreviated can be viewed as a detailed balance between all the ways that things are made and all the ways that things are destroyed and at equilibrium there being made just as fast as they're being destroyed it's not that nothing's happening plenty but it's all if you change
1 of the rate constants for example you have to kind cells that have to do with your ball on steel glass and on steel plant and 1 of them tends to make the bones bigger and stronger and the other 1 tends to make your bones disappear get weaker and smaller if you go up into space and float around the space station for each article of Mars which would be a good idea because there's no gravity the US steel blast so guess what there is no reason on earth violent phone I'm not feeling anything the are of class however are always running and that's the rule Is that the machinery that staring you down is always run so that the minute you start building itself up you go to a lower state that's again adaptive because you don't want to be trying to maintain a gigantic bones and muscles that you don't need where you can find he peak to support all that if you're running around in the while so if you don't need it you can just get rid just like the brain and that's why when they come back from the space station basically on a gurney or in a wheelchair because it so weak the muscles didn't have anything to stand on I I don't wear I'm say that all the time "quotation mark my blood doesn't even have to work to to get back from my hands up my heart and so my heart in this little pathetic and end I come back down here said then I feel absolutely miserable wait bones