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Lecture 05. Acids and Bases. Pt. 2.

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Lecture 05. Acids and Bases. Pt. 2.
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UCI Chem 1C General Chemistry (Spring 2013) Lec 05. General Chemistry -- Acids and Bases -- Part 2 Instructor: Ramesh D. Arasasingham, Ph.D. Description: UCI Chem 1C is the third and final quarter of General Chemistry series and covers the following topics: equilibria, aqueous acid-base equilibria, solubility equilibria, oxidation reduction reactions, electrochemistry; kinetics; special topics. Index of Topics: 0:01:27 Weak Acids Dissociate Partially 0:06:18 Summary of Ka and Strength of Acid 0:12:00 Bases Overview 0:14:20 NH2- and Strong Base Example 0:20:23 Weak Base NH3 Example 0:37:55 Rankning COmpounds Based on Base Strength 0:47:46 Weak Acid/Base Equilibria
pH 7 Weak Stahl solution Essigsäure Salzsäure chemical man molecule Cracken level fall association Gases asset proton water Wasserstoff van Säuren Computer animation blue Zigarre screening addresses form
pH 7 Digital elevation model stretch Insulinkomabehandlung Weak Bohr solution case man Magnetometer Altbier Common conjugate Medroxyprogesterone chemical formulae concentration Maische Gases asset Electronegativity OH- end water van Säuren Wasserstand Iron scale basic form stuff ammonia methanol
Bohr solution Memorial cluster Hydroxyethylcellulosen molecule period Hematite Acid dissociation constant Holes concentration association Maische chemische Reaktion OH- firm systems van Säuren yield compounds Dielectric spectroscopy Dissoziationskonstante History form bond Polyurethane Weak electron donor case conservation man analogue Natriumhydroxid age Magnetometer molar overexpression conjugate mineralischer Oceanic basin chemical formulae areas type power mixture burning Sauerstoffgehalts glass asset proton hybrid water initial covalent chemical structures basic base pair den ammonia
Acetal Bohr Essigsäure Salzsäure Karsthöhle case man Magnetometer parents conjugate period chemical formulae Hematite areas balance Maische Gases asset proton Begasung water Säuren Gamma compounds Hausmittel basic form base pair label
pH 7 Acetal sodium hydride Weak des solution operation case chemical man Magnetometer Assimilation (biology) Magma Butcher conjugate mineralischer processes Oceanic basin Hematite Malt phase Index Arginine Stickstofffixierung asset Ethylen-Vinylacetat-Copolymere Zigarette water Säuren initial compounds Zigarre scale basic stuff
Acetal concentration constitutional Essigsäure solution proton Gletscherzunge case chemische Reaktion man water Wasserstoff Säuren Computer animation initial Magnetometer Iron Zigarre conjugate base pair form processes
Acetal composition concentration Essigsäure Hydroxyethylcellulosen man water van Computer animation Gamma Iron AdoMet processes
OK come on let's go ahead and start the fact that attention so I want to remind you that the chemistry department offers help the other the children so anybody needs assistance in all the information is provided here there is
also a link from the class website you get all this information is on the class website as well and so you need held on a dropping basis you can seek help from 2nd during services or there's also a lot of cage and yet so please take advantage of these resources and make sure that you don't fall through the cracks are either of the great so you guys remember last time we talked about acids and bases and so we will look at the difference between strong acids and weak acids and we said that the difference between a strong acid and a weak acid is that a strong acid and Associates completely so dissociated 100 % whereas we gasses the only dissociate partially and the difference is pretty dramatic so it's either 100 cent on the dissociation something like 10 per cent or less very often it's much smaller alright the weaken the asset the partial dissociation is going to be even less of it so now it's important that you have a mental picture of what it looks like a molecular level so we call this a microscopic view and we're looking at the dissociation with a look at the difference between a strong acid and a weak acid and we look at it at a molecular level so most of the strong acid which is hydrochloric acid and said you place hydrochloric acid in water you know that every single molecule of hydrochloric acid that placed in water will dissociate so you see 1 molecule right and see what happens to out and becomes an SEC our but then it gets deep wrote later the Proton is removed right and you saw that forms a high during no matter where we're looking at it in a "quotation mark solution and so in this picture the number of water molecules would be millions upon millions arrived and the amount of aid CO molecules will be very few compared to 1 of which is a solvent so it's like millions upon millions of water molecules and perhaps 1 of the CO now the reason that in this picture window we only 1 molecule because if we want to show more than someone 1 of the field molecule because they're going to be far apart from each other to at a solution because the relative ratio of 8 steel molecules addresses the solvent it's such a big number that I wanted to show you another 8 sealed molecule I would mean a giant screen all right to screen the size of a football field then you can see another 8 market because so far apart from each other at a molecular level which is zooming in on 1 region and therefore we see only 1 your molecules so once again every single so it just looking out 1 answer every single 8 CO molecule that placed in water Will blues that Proton City conceived using them a time to form a hunter on your mind right and that we can see that the proton gets transferred from 1 water molecule to another now like take this any gasses now what I what is shown here in city gas molecules so this is Coburn territory hydrogen to on this side of this is is on the other side you can see on this whole molecule as a whole is a molecule city gasses molecules so you have CH 3 C O 4 0 8 is behind him behind now because acetic acid is a weak acid and we now that only partially dissociated other words if you have 100 molecules of ASU's acidic gasses maybe 1 would associate here but thousands of year 100 acidic gas molecules only about 1 per cent will dissociate alright and because of that you can see that if I wanted show this picture and I'm looking at 1 molecule the chances are that that molecule is going to be 1 that does not dissociate so it is with the other 1 molecule of acidic gasses and therefore if you look at this picture you'll see that this city gas montages wanders around bumping into water are right and that's the city gas molecule but you can see but there is no through time lost from that and that is because it's a weak acid and if I wanted to show In but the weak acid I would have have maybe 102 thousand acidic acid molecules and among those only once with associate get that so that's the difference between a strong acid and a weak acid so when we show this picture I want you to remember the reason we show you 1 molecule of the bypasses the strong acid weak acid is because the windows to small OK so to recapture talked about last time we said that's only a summary of what we said last time was that the new 1 is summarized the takeover message from last class that was that 1 strong acids I have to be greater than 1 we gasses I have saying less than 1 a right to smaller the value but the the weaker
the acid all right 3 substances that has carried less then 1 times 10 to native 14 do not act as an asset in water right and that is because water is a strong their asset so what is the strong acids and therefore act as the acid arrived so UK value is less than 10 tonight 14 . substance cannot act as an acid and water OK so that's the most important take a message and finally I wanted you to remember but can I move this supply and I wanted you to remember that we need to print out this table and keep it with you at all times because this is a lot of common acids all right and as I said last time when we list asses we always listen 1st as the acid form and a member of the ,comma Spears so when you have an asset and you know that you have a conjugate base associated with that as well all right and so the acid form is written over here the the formula the acid form is written here the formula of the conjugate base is written here and the corresponding K values for each 1 of those acids are listed here and we said OK is greater than 1 it's going to act as a strong acid and so these are the acids that would dissociate completely and highlighted that in rare occasion not cut off point to its high during a mine so I don't mind has a k a greater it has K 1 and that is a strong acid as well but in no these are assets of between High junior mining and water you have the range of weak gasses and so started from 10th the negative ones to conceal potential negative 13 these are all examples of weak assets of these assets if you place them in water will partially dissociate did you had to undermine our right now at the bottom is water and the chaos pure water is 1 time said the negative 14 all right and so anything below that like methanol of ammonia and these will not act so these substances that have K values less than the the value of water and that the substances will not act as an acid in water is an exempt so there don't might act as an acid in water level water is a stronger acid so in water they would act as a base to understand because water now is a strong acid and those substances all right no 1 of the things that you have to practice and you know how to do it is to two-way relative acid stressed all right in order to rank relative acids trends you have to use this table you can memorize the stuff so you have to look at the way you rank assets and you know you're asked to do a series of 5 assets and said rank this in relative acid stretch starting from the strongest to the weakest are right and that means that you're going to look at the case values or are sometimes you given the PKK about its members is is the negative lot so if you look at the scale you can say that became values decrease as you start from here and you go down but the PKK is reversed because you're taking the negative log all right to look at the gate values strong acids have negative values of small numbers but weakest the weakest acid will have a bigger PKC alright so can oversee the Steelers reversed alright strong acids will have a PGA that's a negative number are among the weak acids anything that has a higher PGA is a weaker acid than anything that has a smaller piece of became a value right so that's worth remembering no it is the same thing with bassist contributed remember last class at the end of class started looking at places and we can drop the the same kind of parallel between acids and bases so use databases we said that and take was bid and cost solution it is basic therefore it contains an excess Our hydroxide irons over high join your minds so in other words we say that the hydroxide and concentration has to be greater than the high journeyman concentration that's why that solution in Haiti in water for the basic rights To we said that can be a strong basis for weak basis and if we take a strong base of stabile looking at strong bases take a strong base are right that we use the
same analogy as assets said take strong bases 1 is that a strong base has case the greater than 1 right and to we said but a strong base this associates or ionizes completely and when we say completely remained 100 per cent right so provided an example a a strong base an example of a strong base would be an age to minus right so as soon as this a strong basis and this is going to act as a base in water I can write equilibrium that would be established as an an age to minors in water so this is the biggest thing has to be the proton accepted so this is the biggest Proton accepted therefore waters can be the acid which is the proton donor would end up with this accepting the protons and now it becomes an 8 3 8 4 as momentous as a negative charge it's picking up in each cluster becomes neutral all right and because this is lost in each plus what you end up with is or which miners and because you're producing miners now you have an excess which miners alive to undermine this would be a basic solution now this is a strong base and the reason it's a strong base if you look at it kg value this is of the order of 10 to the power of 20 so this is an enormously big number and you can see that a k a value indicates that the equal of relies entirely on the product side so when it was established you can have lots and lots of adjoining mind and NHS reform and very little Of the reactants all right and and so because this is a strong base so let's just go back this will be the conjugate assets and this would be a conjugal base and if you look at the pairs the conjugate acid base pairs you can see that the the acid form is an its 3 the basic form is initial miners and H 2 0 and A which minus so these are the kinds of acid base pairs in solution and because we are looking at a strong pace let's say I start with an initial amount so of my initial concentration that sale of NH to finance is something like . 1 0 mole a so this is more warm and the initial concentrations of . 1 Moeller were not concerned about the concentration awarded we know that to begin with I mean have no products being formed now and I love system the good equilibrium I know it's going to proceed in the forward direction says it's it's proceeding in the forward direction I know that the change in concentration it is going to be negative effects plus 6 plus tax but because this is a strong base and we know that this association is complete we now that X equals .period 1 molar in other words all of its associated arrived and so because of that and equilibrium I know that this is going to be approximately 0 and wouldn't get all of this kind where 2 . 1 0 Moeller and . 1 0 Moeller all right so because this is a strong base and the dissociation is complete you can see that the hydroxide and concentration would equal X which is . 1 more and therefore peel wage this is tend to 91 so appeal wage should be widened and therefore pH would be 13 itself you can calculate because this is a strong basic dissociate completely we can figure out what the hydroxyl ion concentration is if you know the hydroxide and concentration at during my concentration and Nietzsche and peeling are know another example but is if you take sodium hydroxide no sodium hydroxide it is assault for an ionic compounds and place sodium hydroxide and water to it will disassociate completely to give me an A-plus daiquiris and voyage minus its courses as well so this is another example hydroxide as sodium hydroxide is a strong base as well and unlike previously where we've looked at called Midland compounds are right where you have a covalent bond being formed right broken informed here this is an ionic compounds and submit it to the hydroxide and take his on structure and put it in water and I said giant lattice structure breaks apart disintegrates and gives you any lost in which miners as well so once again if you start with an initial let's say I start with . 1 molar India wage and then have 0 that and this is going to dissociate it can proceed in the forward direction so and equilibrium because the dissociation is complete now this will be 0 and you end up with it .period 1 molar at any Plus Inc . 1 molar of into 2 significant figures so .period 1 molar of hydroxide and now you know In this solution to the hydroxide and concentration is going to . 1 more all right and you know the hydroxide and concentrations by 1 you the pH especially 13 and PO which is going 1 so these examples of strong acids assault so strong bases are right now like acid we can also look at now week basis so if you take the 2nd example which of the week bases and if you take week bases we bases have paid less than 1 hour right so in week faces KB areas less than whites circular said Katie is less than 1 and 2 some weak bases disassociate only partially right so let's take an example of a weak base so an example base would be in NH street art so we look at any age to minors which is a strong base our right to take any treaty in history is a weak base In view place in a street in Wan Chai equilibrium that you would establish would be the following so if I take NH 3 requests and places in water it acts as a basis of this would be the biggest and that will be the acid and because it's acting as a base this would be the proton accepted this will be the proton donors so it managed 3 picks up an age plus what would that conjugate passage of industry looked like conceding formula the conjugate it is you to add 1 more hybrid in the image for the taking you took ,comma in clustered selected the charger that come out to be the positive so it's going to end up with need for class so this is the basis its attack accepting a protons and therefore its formula will come out to be a need for plus request plus voyage minus Equus case and this would be be the conjugate assets and this would be the conjugate base so you
want to look at the conjugate acid or base pairs it would be 1 you have the acid form of this would be an age 4 plus N N H 3 and 2 you would have H 2 0 and which minus cities of the country that has been spared so if you want to see what's going on you start with N H 3 which has this Lewis structure right so all of know the listed 2 minutes 3 looks like it's neutral to a car that be now in this picks up a proton goes to form this car that's each for lost and you want to write this in the general form you end up with V-8 last time writes about picking up a proton ammonia when it picks up 8 plus gives you that our right which is a useful you look at the stadium where it has a stake number 4 it has no longer pairs so would take the shape of this molecule should look like tetrahedral so this would be attaching to Michael where's this would be true of right OK so it might take this equilibrium which is NH 3 Celeste go back to this equilibrium the winner and this is the maybe because we now there were writing this where it's the formation of hydroxide in ammonia behaviors as of basis water and therefore this reaction has to be Europe's dissociation reaction and since this is a big association reaction I can say that could be the walls of the concentration of NH 4 plus times hydroxide divided by an extreme it gives me the base dissociation constant for this reaction so this is the basic dissociation constant for the base ionization constant now if you take this equation and we know that this because of this is a week base we know that this number has to be less than 1 kids that the small number and that associates only partially because the equilibrium relies entirely on the reactants side you have lots of any 3 but very little aid for lasting form got but now we can take this equation that is written and memory now we have seen that kW equals high joining mind concentration times hydroxide and concentration right therefore we know that the hydroxide and concentration is kW divided by the high journeyman concentration so we want relations that equation that we just won't on top but no we 1 replace terms that represent high drawing him if I take this term and replace hydroxide with that now I have an equation that gives me the values in terms of height drawing him rather than hydroxide said I go back to that equation all right I can say is that the a B equals NH for the last time zone replace hydroxide with that so the kW invite replace this with that I end up with kW divided by N H 3 times had drawn uments essentially what I'm doing is and replacing the hydroxide terms In not in terms of the conservation of hydroxide but because I know the relationship between hydroxide and join him and replace it with a term that represents the high during my concentration all right now if you look at this term solicited kW out but if you look at this term this is actually 1 hole where King In other words remember we have our conjugate acid-base periods where are conjugate acid base pair in this solution is we have an age for glass and 83 3 are right now might take that energy for plus can all of you see that that's the acid part of it that's the conjugate passes right now when I'd taken hostage and place it in water What is what happens and now I'm looking at an asset and if I take the for this continent here if I take the acid form about here and put it in water can somebody tell me what would I expect on the product side of his acting as an asset and how to asses the year when they produce its yield plus a right to circadian tell me the product side what would I have had a 0 plus 1 in history right so this is while taking human memories all come in pairs you always have a condom acid-base there survived take the acid form Of this conjugate acid-base in water this would behave as this it's still plus N N H 3 the request now what was that equation describes if I look at this equilibrium however described the equilibrium constants that describes his equilibrium Kate and receiver so this represents skated so vital the acid forms other conduit acid-base here and I take the acid and place the acid in water this equilibrium I'm describes the right now the states of this is this part this is the acid parts now let me take the basic and invited the biggest part and invited the biggest and place it in water when is equilibrium I would establish looking at a base and the other basin water can you tell me what the products of that reaction now exactly as a base so it's a bit of it has to be a proton accepted so you end up with what In it's 4 an hydroxide conceded so in this continent estimation if you put that arson form only in water would establish center with them if I take only the base form and place it in water it's going to give me in for plus the quest plus a which minus quest and now or how describe this equilibrium constants that describes this equilibrium all right so long this would be KB are right and so that describes this so no no can you see that it might take this equilibrium in the acid forms this describes Hsu sought by taking a I OK equals 1 here k equals Hydro concentrations times in NH 3 divided by NH 4 plus all right if take the acid form is a tutorial class times and 3 divided about the need for plus you see this term is actually this is an extreme it's dual-class divided by for plus 2nd you see that I go back to this equation I can't say equality Kate W. aide and therefore kW equals to a times KB the go see them alright so divided by equilibrium expression kidney and now replaced the hydroxide terms with the term that describes the high during my concentration then what I can do is act and driving expression where to aim times KB maintained uglier all right so what you want to keep in mind is that when you take it from every continent acid base pair you haven't acid form which is
that represent the aid you have a basic form and that would represent KB all right so it might take it might take a city gas incident let's take another acid-base specified take a conjugated acid base pair and let's say now I'm looking at the acid forms is acidic gasses if this is the acid can you tell me what with the corresponding conjugate base turned out to be what is that of the conjugate base of acidic gasses acetate and what is the formula varsity the experience similar to my so it's lost a proton so it would be this now the acid form of acetic acid is when it establishes an equilibrium this would be acetic acid In water now this is the acid this is the basis so you can end up with junior mine alright plaster acetate and I said this is the equilibrium that will be established if you take that acid part only and place in water when you do that this would be k equals 1 point 7 6 times tend negative fine so that it is taking remedy label that I showed you you can look up the K a value for city gasses and it comes out to be 1 . 7 6 5 times tend the fight now I take its conduit so now I've taken care of the
assets that I take in this conduit acid-base there if I wanna look at the base part of it and he might take the basic part of that would be the biggest in water now since this is acting as a base this will be the proton accepted so that the ascertained and I'm accepts a proton what is it becomes as a gas suggesting that accepted the Proton from water so that this part of it will accept a proton from water and then go to the city gas said and what now the water is lost through time so it is it becomes or minus innocent it's producing owing to mind as this would be the biggest far-right candidates of various this is the case b so we know what it but the acid form we can figure out what became the for the basic form is because we know that take aim times KB equals W therefore can be equals kW overcame a which is 1 times 10 to the native 14 divided by 1 . 7 6 times tents in its fight for our rights and so on before that it had calculated this number comes out to be 5 . 6 8 times 10 to the negative 10 right and so you know what the K of the acid forms Of this time acid-base period as you can always figure out where the corresponding KB is right so this is important because what you will realizes that this is the only table that need all right and so you will look at your textbook review go through like handbooks you will never find the kidney values listed all right do only balance that unlisted value so you never find KB values listed anywhere and the reason is is that if you know what areas but the continent as you can always count Wikipedians all right so if you look at this table we said that these are all listed as conjugate acid-base parents so all the cave values argument all right and said you know that the Italian sold you go to just acid so we just think acidic gasses so that I vibrant city gas on this list I will just go look for on 10th the negative vibes and here we are where so this is a gasses you have the acid form and you have it's kind debates now would you will find in the table anywhere it's all Medicaid value but you can't take the when you need to do take the kid value and kW divided by key will you alright and similarly for any based solely by God to hydrochloric acid became a valued his tenderness and so I wanted to go out its kidney value in Italy kW divided by that taking will give me the W I'm sorry KB To understand that so you will never find a k a KB values many table now are it just like we can compounds based on relative acids trends we can also read compounds based on a relative basis trends all right and so when your ranking on reality-based trends yet to start thinking about and flip it and Figueroa KBE is and rank them so it might take the ass is only if I take ass only can ever going to see that you start at the top it values a lot strong acids as you go down like to a values decrease until you hit here and that is the weakest acid that you can find the kid values keep decreasing but these will have the values less than 10 the native 14 and therefore these what on disasters in water now by taking the is now as I look at the contract bases now
these represent bases and therefore they represent kidney values are right to continue seeing that the strongest sold now since its carried times can be equals kw can oversee that it carries a large bowl kidney turned out to be small I'm so this year you can see not everything is reversed right will you take conjugate bases now hydroxide will have a key the of 1 so that line is a cut off between strong bases and weak basis so the strong bases will be the ones down here so the euro I considered strong basis alright so all these other strong bases anything relocating 1 will be a week based so starting from here as you go on the base gets weaker and weaker and weaker and weaker and weaker until you hit here so it might take this phase this havoc a value of 10 to the 13 so what does that tell Medicaid the government has to be tend to make me want to see that now I take that as this assistant to the negative ones so it's Katie value we tend to negative 13 so the weakest this would be the best and among them all the weaker bases the job starting from here to here is all week bases but this would be the stronger of the weaker bases and this would be the weakest of the weak basis now wants you hit here now what want and so any of these will have kidney values less than 10 to the native 14 What is that means those substances will not act as a basin water because water now was a stronger base you see that and so on Water will act as the base In those solutions design accessory so it's the same perilous acids but now everything has been reversed all right and so 1 of the things that you have to practice is that when I ask you to where these in terms of relative basis cities all right rather than acids a pretty straightforward because you can just look at that table and figure it out now the talking about ranking in terms of relative basis you have to be able to flip it around and know how to do that now just as we have looked at kW came and PKW and Kasey some kid we can say that we now know that a times KB gives us kW are right now he said that these ranges of very broad and very often in acid-base chemistry we always like to take the luggage scale so we can compress that scale so we said that it by taking the negative log of CAE Inc and remember now I'm gone moving to lobby the scale so when you have a multiplication in
logarithmic scale it becomes a plus sign this would be negative log KB centered in the last month of this negative log of that that would undo side I have to do the same operations have been negative log TWA right so that means PK plus PKB equals PKW which is 1 times 10 to the negative for so now to just make life a little complicated not only should you be able to read things based on but now you have to be able to rank them in terms of Peking and remember everything that's looked around saw us go back to the table some of so personal that we know that now regarded the scale and if we look at assets which said that if you look at dedicate use the numbers decrease as you go down if you look at the case because you taking the negative longer that now the scale is reversed right now we're looking at K you know how to right so you look at as you go down and as the cable values get smaller and smaller and smaller it gets to be weaker acids all right if you take the game is it's flipped around our right as the numbers get bigger and bigger and bigger it means they're getting to be a weaker asset right now if you go there said it came decreases that means killing goes up arrange so as KB goes up so that the order is reversed so In this table we have a strong bases will be at the bottom and we basis it will be at the top right now you take so kiddie values would decrease as you go down now we take the middle that that's what's around us PKB PKB increases going down 2 guys did that so when you're at home I want to come to think about this because we have not actually for skills that were looking at were looking at Carrefour acids and the kids that's 1 scale if you're looking at the conjugate bears on Nextel is KBE and PKB and you have to be able to see the relationship between everything which enables the lessons K and Cabido initiative assimilation should pick PKP right an unusually quickly able to count on cigarette what the kids and pictures of the kids are going to be right so you know that this number is 18 you know that the PKB on this day With the 14 miners .period went to see that if you know OK a of acidic as his 4 . 7 5 then the KB of the acetate and 14 minus 4 . 7 5 are right but the most important take-home message is that you have to be able to rent compounds based on this relative scale arrived so and in the whole world it in the discussion worksheet for next week I have placed some examples where I want to convert from 1 to the other and rank these in terms of relative acid-base trends or given 5 compounds you should pick out the ones that is the strongest acid or pick the 1 that is the weakest pace and so on 150 members to come down we should be able to do that the case directs another we've looked at that and you have a feel for the test and in fact I would suggest you print this out and painted on the wall next to where he studied and people looking at this at the time when he doing homework look at that hour right because there is a unit in while last with the last year rank relative acids and bases and so on and so you don't memorize the stuff you have to look at the key Italians and so on an exam to I will attach a copy of this so that you have that to look up as you rank as the basis for right now we still have a few minutes so I want to do is just take 1 example I have some problems and now we're in a position to work problems and this 1 is a problem
that we worked before but I don't want to go through the process of how you calculate the pH of a weak acid a so that this problem is I don't want to copy down because I put all those examples of working class is already in the class website you can print out these problems so I don't want to spend time copying the problem because you already have a copy of it that want to show you the general strategy of solving these problems so we're told that acidic acid in water donates a single hydrogen iron with the case of 1 . 7 6 times to finish this fight so melodies all comers Condit acid base pairs whatever starting with the acid form its conjugate based on the acid form therefore it's going to act as acid in water so that for any program problems the starting point is writing down the appropriate equilibrium equation so they tell us that we are taking a city gas in it in water and they tell us that donate a proton to water to give you high join in mind irons and we know that the other product is going to be an acetate and we know that K is 1 . 7 6 times 10 to negative vibes now we are told that the initial concentration of acetic acid before anything happens is 1 mall in 1 leader somewhat with the Constitution come to it was all in 1 so it's going to be a 1 it's
given the trees significant figures and before anything happens this is what we have are right now we need to figure out the pH of the solution in 1 that at what is pH represent yes what is pH represent the high John concentration so we need to figure out front for the pH need to figure out what they I drew the line concentration and that we have to figure out from this so we know that the reaction proceeds in the forward direction and we know that there is
no we don't need to concern ourselves with the concentration of water and therefore now we follow the usual process as we noted in the preceding the forward direction therefore if X is consumed uniform at an X on the product side therefore Ed equilibrium concentrations are going to be 1 minus X X X No this number represents life this number 1 minus X represents the amount of acetic acid that's left over to see that it's not the amount of acetic acid that reacted the amount of acetic acid that we acted as 1 X right so what we have is after Queen's establish its demand of a city gas that's left all work over the UN reacted part of so soul now I can say Hey equaled 1 . 7 6 times that the negative 5 equals a join concentration times the acetate iron concentration divided by the concentration of acetic acid all right which gives me at squared Over 1 minus X right now can I make an approximation here what is they tend to the negative fight so can I ask you
guys to figure out at home make the approximation can you with high joining my concentration as you know the hydro and my concentration can you count the pH yes and work together that we can also began send the composition of the beginning of last next time the answers are right