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Lec. 11. Born-Haber Cycle, Mean Bond Enthalpies & Calorimetry

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Lec. 11. Born-Haber Cycle, Mean Bond Enthalpies & Calorimetry
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UCI Chem 1B General Chemistry (Spring 2012) Lec 11. General Chemistry Intermolecular Forces -- Born-Haber Cycle, Mean Bond Enthalpies and Calorimetry -- 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.
Kalorimetrie islands Haber-Bosch Flammability limit chemical bond solutions chemische Reaktion period Vakuumverpackung calculations
Computer animation electron Haber-Bosch Adamantane scale chemische Reaktion crystal form stuff chemische Reaktion
Supplement Verdampfungsenthalpie chlorine atoms chemische Reaktion Potassium firing age Ionisierungsenergie electron Magnetometer Potassium chloride storage atom processes Verdampfungsenthalpie type molecular Haber-Bosch balance chemische Reaktion end Wasserstoff Computer animation metabolic pathway function standards salts EAS Brown adipose tissue oxygen form calculations
transition metal Urocortin Verdampfungsenthalpie Sodium fluoride Nitrosoethylharnstoff Molare Wärmekapazität interface water systems Eisfläche Computer animation temperatures Potassium chloride salts Salzschmelze Pipette
Urocortin nitrogen chemical bond hydrogen bonding Angular mil carbon fine case chemische Reaktion chemical Vakuumverpackung chemische Reaktion Wasserstoff Computer animation radicals association compounds Library mass spectrometer compounds Library CH4 oxygen atom
sense type bond Verdampfungsenthalpie ethane chemical bond carbon Adamantane chemische Reaktion Propionaldehyd Wasserstoff Wasserstoff Thylakoid Computer animation Strength stone compounds Library compounds Library Angiotensin-converting enzyme
reactor bond chemical bond balance chemische Reaktion chemical chemische Reaktion combustion Computer animation age compounds storage atom
bond chemical formulae Toluol balance burnings case food Ethanol Thylakoid combustion Strength firing water Meeting/Interview Hydroxyoxonorvalin <5-Hydroxy-4-oxonorvalin> chemical formulae type Storm surge nitrogen formal carbon Rohtabak end Wasserstoff conditions Computer animation yield Attitude (psychology) molecule chemical structures Carbon dioxide oxygen Farmer atom methanol stuff
delta bond Ibuprofen case chemische Reaktion Ethanol molecule combustion level Computer animation age initial Butcher oxygen
chemical element type Double bond chemical bond Adamantane case chemische Reaktion pressure chemical Computer animation age important Common Carcinoma in situ chemist atom standards
aluminium Copper(I) oxide copper case blocks blocks flow Starterkultur temperatures stone active site fall flame metals Holes copper aluminium Molare Wärmekapazität man pressure specific temperatures Computer animation copper sulphate Kunststoffe Pressure oxygen stuff
capacities burnings metals molecule Kunststoffe temperatures protein old metals Harmful capacities rates balance Molare Wärmekapazität chemical Receptor Toast temperatures water Joints Paste Drops Computer animation Kunststoffe regulation flexibility
areas metals Urocortin aluminium container copper Molare Wärmekapazität chemical Multiple chemical sensitivity temperatures flow Computer animation temperatures stone
damage pathogens potential solutions case chemical Multiple chemical sensitivity pressure water flow Computer animation temperatures Sieden
temperatures flow Urocortin Computer animation model temperatures stone aluminium aspirin chemische Reaktion chemical Joints
chemical formulae capacities aluminium steps copper case solutions chemical blocks Combining Computer animation firing Meeting/Interview function temperatures Grease (lubricant) stone mineralischer
Kalorimetrie delta capacities operation flat Multiple chemical sensitivity food molecule machine cellulose temperatures protein fiber stone amino acids Metabolit leak chemische Reaktion chemical firm water Computer animation spirit Genort Calorimeter stuff
Kalorimetrie Urocortin bond capacities Molare Wärmekapazität chemische Reaktion firm chemische Reaktion temperatures Magnesium firm Computer animation temperatures stone oxygen Calorimeter oxygen AdoMet
Kalorimetrie type capacities Gases capacities Molare Wärmekapazität chemical Multiple chemical sensitivity pressure metals temperatures gap Chlorhexidin Computer animation temperatures Attitude (psychology) stone Magnesium oxide
power type hydrides Wasserscheide properties case man firm Wasserstoff ingredients Computer animation water Sieden powder Fusion nickel nickel ingredients
reactor type surface Neprilysin Hydroglimmer multiple Angular mil chemische Reaktion source Columbia Records man chemische Reaktion Wasserstoff case Computer animation Diatomics-in-molecules-Methode defects nickel board active site Kernreaktionsanalyse
power Urocortin power Wasserstoff Computer animation firing glass Fusion nickel storage chemische Reaktion source
toxicity Computer animation parents repeat case repeat
pretty easy for a period of the calculation that he calculated the energy of an isolated state plus ion vacuum and isolated the online silent backing and if you tell them crystal structure and that there is something different than this kind of problem .period love while harming sum of all those parties reported the news and then only a fraction figure whole energy of attractions to world and then compared with the With the isolated islands Our solution then was to try to come up with some reactions using passes laws come up
with some reaction so that we can vary widely and a total of 1 we want to just play a game of 6 figuring out what we can measure for this reaction that we can't easily carried out in the last and what we're going do if we're going to do it by stages we're going to finish the day the Adam and then working moving electrons off 1 on the other hand working at the track of all altogether energy In all the draft is no we're going to about and see what we can get now the problem here is that some of these energies a rather large and so although we can get a number the number may not be as good as we would like
because when you have Back in large numbers to precision I get on the scale I don't the number I put a submarine on sale and then the summary was track and I do love their minds about the fact thing the times going in or out of a bunch of other stuff and so we have to worry about that here because some of these
numbers are going to be going to do that the 1st thing we're going to these were going to decompose the salt into its balance because that's the formation that we can help the formation of potassium chloride we can certainly measures that that's in tables .period Delta formations in all kinds available for all of the people ,comma so we can get a good number for that and because we're going backwards it's minus the heat of formation we made potassium metal in the standard state and a half from all of chlorine molecular chlorine gas again and the standard state and then we have to take the potassium in the standard state and we have to turn it into a potassium vapor and I've mislabelled goods but I'll fix it this should be dealt a picture of supplement not dangerously start a path and solid standards and then we have to to make a single chlorine atoms each other molecular chlorine so we may have a mole but the helped to make a whole lot of Seattle .period lorries had far far more reactive is molecular the the Air Force has program on ultra-high-energy fuel you may know that in the space shuttle there news of various kinds talents for example hydrogen and oxygen into you and you get a lot of roughed out there but in very few could have instead of a Francophile instead of paying lot of guys ,comma if you have a tank of age and I thank you all God it would later say that you did not have much much more the problem is how how do you stop the binding and going back to the more stable form all year waiting on want and if that's a very energetic process the new rocket catches fire setting so it's easier said than done but anyway there has been some work on that then we take the potassium battle in the gas phase the only thing electron office and that's the ionization energy of the tasks and that can be measured quite well it's a fairly big number because as you can imagine take an electron off the air is not quite so easily but anyway that's called the ionization energy and it can be measured quite well and then we have to to take chlorine it we have to add an electron the atomic chlorine in it love that boy I love to get electronic complete that that's quite energetic and that can also be measured that's the electron affinity Of the chlorine atom and then if we just a call these the delta H is that we've got we know that if we add the chemical equations we just at the Delta ages because Delta regions state functions and it doesn't matter how we get to the final state including by an imaginary bat this is like this 1 so we cancel out everything that appears on both sides and we end up with the reaction that we want to as a solid going to Kate plus in the gas phase and see all mines in the gas phase and there we just add up the alternate 1 plus 2 plus 2 equals 4 was 5 and and we get a and then we can
compare that number with the fearsome and then argue about who's right and who's wrong the experiment analysis of the nearest neighbor better better make calculation more accurate you made some approximations there you'd better go back and do it right and their access to the experimentalist you better do that experiment more carefully I don't really believe that number you get in there until they come into somebody's wrong or something's not taken into account sometimes there's something not taken into account when you make a discovery so science when everything in Greece is quite what's exciting it is when you have to sides and both think their right and something doesn't agree the question is what's out of whack and that means that you're going to make a new discovery problem once you figure out what's going on OK the latter sent Ltd
to have something to do with the melting point of these salts they all melted very high temperature but potassium chloride heated up enough this will melt into a liquid like ice melts into water the United clearly would has essentially no vapor pressure Peter Boyle as thousands of Celsius and it can be a dandy way too move he'd around molten salts of being explored as ways of storing the moving the and so forth because they very high heat capacities because moving these of part takes a lot of the problem is you have to keep them quiet spot or they solidified interface solidifying your piping system then you're in trouble suddenly and so there is a trade-off you usually don't want to fight on Nov . molten salt and flooded some that I found here as a scattered applause and I plotted the lettuce and copies on 1 axis and then the melting point things like sodium fluoride and so forth I label them all but it looks like there's more and you know there's kind of a trend the correlation is weak if these results were in biology and not panic this would be proof positive of something other the credibility of the dizzy diabetes we've lost the handle of like however can
last week we'd love to see things better we like that takes something else into account maybe the set different crystal structures and maybe if we could crystal structure into account some way we can do with the melting point that baby these would start lining up there and then we have a better idea of what the true forces and energies and play actually were but you can see we've got a range here and there some correlation but it's it's definitely not something to write home about focus there are also
available trying to keep track of the energy it would take break each time ,comma ball that 1st in in chemical and the way it has been done is that we get a library of representative compounds and we try to measure how much energy it takes to break each bomb on the Net a slightly different because if we have something else there it made depend if we have harder in the hydrogen to that carbon hydrogen bonding takes a certain amount of energy to foster the departed HBO in the car with the free free-electron In the interview actually cases pending on what else is took the part is the oxygen on the nitrogen on the Floridian on so long but we can get a representatives idea by just taking a bunch of compounds and and then average and so here's what we might do for method we can do these kinds of reactions usually this is done with a laser scanner molecular me or something like that but in any case we can do do it and we can get an estimate of the energy and we have a certain amount of energy to break 1 ch pondered methane and make the methyl radical free radical and then they added not molecular hydrogen and then if we take this guy we can knock another H off and make this guy is like an angry be H 2 you can't let the playing or practicing their
react like that you they do this in a vacuum where coming through and the ladies in the commentary k together the products which measure separately usually in a mass spectrometry and then you take the methylene and you makes must find Ch another hydrogen and then he finally plucked off the hydrogen from the fine and you get carbon in the gas phase hydrogen gas facing the total of these 4 which are not the same but the club they're fairly close they are totally different the first one on the last 1 may be different the others maybe quite similar and then the average that we get
for this week as is what we call the average strength of the upon method With the Adam all up and divided by 4 and so the search the service extremely useful because if you have a table of bonds and help these as long as you've got that kind of bond you're looking for then you can just add the energy to bustle bonds and then I have the energy to make all the bonds and you can get an estimate for the unhealthy of any chemical reaction you you don't need to know the heat of formation or anything but it's only an estimate because the server approximate these numbers move around and this has been done and you take a bunch of all you don't just take nothing that you take ethane and propane and some other ones and it requires a little bit yet no that's the average for 1 ch of averaged over mad but when they give you a clothing and table for a year bond they have just come in and done a whole bunch what I was about to say is required some judgment when you make a table well ,comma how you measure that put in the air there's just like anything what you come forward to knock out for the senses the account people who were homeless or not things like that and if you know you're going to miss people the estimated as low as you can who you've met as the sleeping under a bridge on the just say no sleeping under a bridge in downtown I don't get any services same thing here and I don't know exactly what they included in the library because they they usually fail to say about the current mean value that they get just to break 1 ch bond is 412 killer jewels per mole for a carbon hydrogen bomb that's a currently accepted value I think and a lots of bonds are listed so lots of there they have mean bond dental please but you have to pay attention to the kind of ball I carbon-oxygen single requires a lot less energy to break then carbon-oxygen double so they will be in the table
trying to tell you what kind of bomb talking about and you have to make sure when you look at your compounds that you're breaking in making the right bonds or you get the wrong fast enough and as
I said if we know these bond and felt these these estimates that we can estimate Delta age for any reaction and we don't have to do anything and that's quite powerful because we may want to get an estimate about whether something even more considerate if the estimates so far off that it's not gonna work the way we want to do that we try to look for something else and so we've stated ,comma time because rather than combusting the thing and measuring and then saying Gee that's no good I'm going to need a tank is because of freighter on that part I use that fuel we can do that just sitting on our desks conceptually Awwad doing this we start with reactor we convert them all into Adams we bust every ball and then we take the and we reassemble them into the new guys obviously hadn't conserved in a chemical reaction that's why we balanced chemical reaction and then if we got more energy and what we used to break apart the reaction is if these are more stable the sponsors stronger than we're going to get beat up when it makes a strong bond shakes everything else out of the this would happen and then as I said we just recombined these we make the new bonds and the we tallied up and we see if the reactions can be XO Thurman Orlando's ceramic and let's try this let's say
take a simple combustion reactions and tried my example will be
methanol the ill-fated that all Bush which was made for farmers were growing corn and terrible for everybody else 1 lesson from that tobacco is that you should not burn food foreign influence is a bad idea you're going to make a campfire you don't throw all the chili con carne and spaghetti and stuff and the fiery know it'll burn you throw into the fire which you can eat and then you got the other stuff but what we are effectively doing by converting a lot of corn into ethanol to use as fuel is we were diverting corn from food and there was civil unrest in Mexico right away because the price of corn tortillas surge and if you want people to get angry makes them hungry that remember the French Revolution and this what happens and we have to watch out for stuff like that OK so let's estimated while the 1st thing you have to to do is balanced and complete combustion always means 0 2 1 8 2 0 if you will has nitrogen and then you have to be careful you're going to get knocked out of some NO NO to has handled what conditions you're operating under In that case we take ethanol CH 3 CH to always and what we need to have 2 moles of C O 2 because we've got to carbon so we have have to them and we have to have let's see 3 that's 6 so we have 3 moles of H 2 0 and then we just figure out the 0 2 after the fact to make it work the 0 2 doesn't matter for a the end of the year formation because the end the formation of it's 0 but for this then we need to look up the the strength of a 0 2 bond because we have to break 3 0 to bonds In a way to reassemble them in the C O 2 H 2 0 therefore in this case accounts and we have to look it up but if you don't know the structure of something that has named ethanol or toluene then you have to look it up and you have to get not just the molecular formula like this but you have to get it in a way that you can see how many people in kind of bond and therefore you have to know the structure of what it is that you react can't smell the name of the formula you know really the structure of this 1 is pretty much the way I've written there's 3 hydrants and on spot the 2 provinces that hooked together there's 2 attitudes on this spot and then discarded to an oxygen and then finally the oxygen 2 1 hydrogen indefinitely and therefore if we call it up with that 1 2 3 4 5 CH bonds 1 cc 1 c o single and 1 0 8 which has the single and then the oxygen give strained also summer long which we have to look up takes energy you break them apart and then the products have 4 don't want but carbon-dioxide haven't special case of you look stable carbon dioxide he said something like because the yield on the carbon-dioxide especially strong and be a little bit more then others CEO in formaldehyde for example we have for those and then here
we've got to all wage single bonds each so we've got and if you're doing this on an exam In sponsors the same that you're making and breaking and fight always single 1 year and ahead 5 years than the eye canceled but because I'm going down saying when I look them up so I don't need to whatever I can cancel out before I actually start adding and subtracting numbers makes it fast the more stuff that cancels the lucky I am and therefore if you do that then you'll figure out what you get and
the easiest way to see what's going on is to draw up an energy level diagram I start with the reactants here ethanol and molecular oxygen and it takes energy the atomized them all into that because I'm breaking bones in those states and and then I get a ton of energy back when I make these guys and therefore this this going down this suspects of their McVie using these Muzak to make the stable molecules and then the difference between this 1 going out and this 1 going down is what I want which is my estimate for Delta age for this combustion reactions and that's just how I do it it turns out then that in this case it's the reactants minus the products because these are all positive numbers breaking bonds there are all listed as positive numbers in the table and you have to be careful about that because usually it's
take the final statement initial statements looks like it's backwards but I usually draw them I drive energy level diagram and I which is which and I see out what I'm going to get fit for the for the entire thing that's the easiest way to do it focus some common these
are only estimates they can be maybe plus or minus 10 per cent in some cases so you can't trust them too closely but there will give you an idea and they may not ever predict subtle things for example remember we have those 2 assistant friends died quarrel happily and we decided that transform would be more stable because there will be there repulsion the between of the balloon-like Florida at but if I do it this way that's because both of them have exactly the same number of bombs then there are predicted to be equally state take exactly the same amount and you break parts this guy for allegedly as it does take part France borrowers in the latest count member Mondale won the double bonds to the singalong UCA single on and all saying that there are predicted to be exactly the same and that shows you that this approach is never going to tell you something to think about structural based on this because it's not accurate enough Deborah possibly do that the reference date for these reactions is always the isolated that whatever you have as reactants wary of his product you're going out to a common denominator up here of isolated Adam that's how you're figuring out what's going on where the hell .period formation please common denominator is the elements in the standard state and because those things have actually been measured by somebody those numbers are way better therefore if you have a choice you have all the answers about the formation every chemical in reaction you always do it that way because there's going to be far far more accurate but you may not in some cases you may not have the numbers you need this then we invented the internal energy you post really of central importance Canada because usually carry out reactions of constant pressure on constant volume therefore were
interested in it he evolved a constant pressure not the heat absorbed or released a constant volume therefore there's hardly any mention of Delta you accept introduced the idea of an internal energy being the sum of the parts were and then after that chemist rapidly moved all the way over Delta age and that's it that's all they talk about after that OK let's talk now about he if we add let's say
local the blockage a constant pressure we will raise the the temperature of the block the and if we pick another yeah for example then aluminum starting at the same temperature they're receiving the same number of jewels of will rise in temperature but not as much on a program they survived a 10 brands copper and many jewels of the the temperature goes up so many degree but they can grant aluminum saying the temperature goes up but not as much and you'll notice that if you buy expensive court where the bottom of the pot is hot all right and then the site of the are aluminum or something else if you if you want a place in hell where the holes a warming hang all those parts are so that everybody walked in your house can and see them all the time and then you spend all your time polishing the copper was always oranges so that it looks beautiful the if you want an even worse sure go over to new export beach where a guy has a solid copper garage course what you're supposed to do with copper if you have a copper roof this year said both the letter and read like the Statue of Liberty supposed to let their senior year copper sulfate copper oxide and that just sits there and that's what is called the but your stuff anything on you know I like the look of Chinese companies but what you have to do it every week you have to get out there and this fall because oxygen will react oriented coated with plastic for some bombs but then it's not quite as appealing as just the bare metal and I run by that house every other week or so and I'm absolutely amazed he must have an army of people polishing Makarov because it's always very very impressive a little green around the edges but nothing worse than that that's a very bad idea to set up a lifestyle like that unless you can afford someone else do the work OK so if we it if we measure the temperature rise per gram we get something called a specific the specific heat as units of jewels program Burke a per cent and the specific heat of aluminum is larger the man copper therefore the bottom of the pan will rise in temperature more quickly if it's aluminum I won't be wasting my gas flame heating up the whole lot of heat up the bottom and start cooking whatever's in there right away more rapidly also copper conducts extremely well that's another issue if I take these 2 blocks and there at different temperatures and I want them to come to a
saying the same temperature all I have to do is bring them into the thermal contact usually that means you you bring them so they touched or the very near each other so their both being up there but in any case eventually if you bring them closer thermal contact they will come to a joint temperature and it'll be in between where the 2 starters if you sit
down on a metal chair In a stadium once said that baking in the sun sometimes the 1st thing you do is down and get up again because it's so hot it's actually burning about but if you sit in a plastic chair has been out of it doesn't seem so hard the question is what's going on and I think I mention this last time but if you Post Raisin Bran and then all talk raisins olives lot harder the economy than the bread the question is what's going on since these are presumably at the same temperature and the answer is that your heat receptors don't respond to temperature they respond to the the molecules that are detecting if it's hot or cold and sending signals to your brains and get your hand off there now or run if flying are responding to heat and so depends how much he gets transferred to you and it also depends how quickly it gets transferred to you because you have blunt slow going through various parts and the years transferred slowly your blood goes through and take some of the new blood goes through and the temperature's locally doesn't go up that much and there is a lot of thought but I can 1 of them too much so it's starting to come you that hot you need a interested or you get up off the chair and there so there are 2 issues as to what as to what goes on the 1st is you're responding to the total amount of the temperature something that has kind he capacity that's extremely hot like a little spark from a sparkler that lands on your arm doesn't the although it's extremely hard doesn't he content because of the very tiny map and there were friends about the often not burned even know it's extremely hard come and the other thing is it depends on the rate at which the heat is transferred as well and metals transfer the extremely effectively so when you sit down and you get a lot of the coming and quickly and neurons that and they have a high heat capacity so they can store a lot of 8 when they go up a few degrees there a lot of things gone into that chair more than the plastic and then when you sit down your call all that he goes into you and then you get off a few proteins start coming undone 1 and you're out you know what temperature state water To be at what temperature before you say no no anybody got any ideas because if you do you consider temperature and something before you get on that sometimes a good idea here hotel and you
drop that analysts in Europe sometimes the waters water you can achieve your way of testing it as you put your foot then when you struggle to get your foot out you can actually slip and fall and get her because of burning foot that extended the hand of panic and lose your balance I think Princess Margaret did get scolded in and in the past palace in England because the water was strong it was too hot not enough Holden and she got and then slipped and fell in the and then you have to to get out of and by then red and I was just way way too hard it turns out it's only 120 degrees at 120 degrees you can put for example you your foot if you've got an injury from playing tennis on the way forward the letter 15 Celsius that's it I am close to 100 thousand 56 years and water that's the didn't get any hotter you can't stand taken that's the temperature Yukon we usually don't have quite that far they liked they liked it he does joints that have problems then were joined together the flexibility back and then I said right away to bring down the inflammation and if you do that regulators here an athlete will heal much more rapidly than if you just sit around and say ouch my buyout offer but they do do do that OK but use
the 1st lot and to predict the joint temperature that 2 or more masses will reach an equilibrium this is down from 39 let's take aluminum and copper take 10 grams of aluminum initially had scolding temperature 50 degrees Celsius and 15 grams of copper initially it .period and cool and let's just bring them into the formal contact with them and let's assume that none of the other meters long that's a big assumption because the apartments in the area of the year going over to cool things down and therefore you have to be extremely careful when you're measuring the guy you don't lose any if you lose in the there were some other place it's not accounted for and you get the wrong number Of we do this in an insulated container and no heat loss to the surroundings the question is what joint temperature will they reach the specific heat of aluminum metal . 9 jewels program for degrees Celsius and the specific heat of copper His only . 3 8 5 jewels program
or degrees Celsius well this
is what's going to happen we have the hot guy in the colder the initially at different pathogens and we bring them into thermal contact he will flow from the hot guys the cold the dollar's flows from hot to cold and then finally they will come to some joint temperature while the when they're out joint temperature like this there dead we can't use them to do it when they're initially like that if instead of just bringing them amid the thermal contact we use something else like we use this guy boil some water Nixon's steam and run turbine and we use this guy to cool off this team so that we get pressure difference across Europe on solutions and then then we can do something where we can actually produce energy once we have things at different temperatures it's like water behind dance rather than just opened the
damages letting go out we can't let the water goes through and generate energy and goes out and we believe off something do something we want to do but in this case were just waste at the potential here to do work and we're just going to turn turn it into this average temperatures the question is what is the average temperature now the key
thing is that he has an algebraic sum it can be plus or minus and therefore you don't wanna try to 2nd guess who's heating up and who is cooling off you can always do that if you're given to Mass because you can assume that guys heating up and you can assume the Hawkeyes cooling off nearly 100 per cent correct but if you're given free passes like you might be given on the next exam and if you try to do it that way you may get into a model because you won't know is that there has been a leader who and then you can guess the sign before you do therefore you don't get you just follow the road procedure Frank the temperature is going to come out somewhere in the 20 but but he that's going to either flow from 2 I'm not trying to guess the aluminum it depends on the specific times the mass of aluminum and then there's always the final temperature of minus the initial temper that's all you have to remember it's always find online instrumental in thermodynamics anyway but that's all you have to remember and I don't care whether this Hugh Sunday is plus or minus so many jewels I do not care all figure that out later when I figure out whether the star is higher or lower than the aluminum when I started with likewise the I write exactly the same thing the only thing that's different ideas I'd love everything could be different that he passed these different that I know of however many grams of copyrightable and then that starting temperatures different but the ending temperature is the same I've got numbers for this this and this this this and this but about numbers for everything here except the star but I need an equation I have 1 unknown he stopped and I need 1 equation and the equation but because no heat is lost the environment and I didn't run a chemical reaction make any this summer the heat is 0 because energy is conserved and I didn't matters of fact any energy therefore my equation is you aluminum what what the summer's conserved last year proper is 0 that'll mean that 1 of them turns out to be negative but I
never write minus and I never try to say all that he's going here and this is heating up and this is cooling down if if I try to do that at the time I get it wrong yeah OK so
let's let's do it here's our 1st law equation you aluminum was you copper 0 then I substituted what I've got here and that should be equal to 0 and then I just insert the number and this case I don't bother converting to Kelvin could but it doesn't matter because I agree :colon degree Celsius the same sort the poor it's only difference on measuring and that's going to be the saying that if I want the answer Celsius while convert felt that the Over back in self-defense just taking time and adding extra steps that can do nothing except make you more error-prone I have . 9 times 10 grams times to minus 50 plus . 3 8 5 times 15 grams 20 equals 0 I put in the numbers by 9 jewels finds the star over degrees C. I write it this way this may be unfamiliar to you but I run this would indicate that he starts Caribbean degrees it is only then will be unit's work out for me that's the term here this once 459 9 times 50 and then this once this term here analysts 115 as this last term there I had it all up and I get 40 . 775 jewels I must say would just be an degrees C. -minus 565 . 5 jewels equals 0 and I can divide both sides by jewels get rid of the jewels and I will find out that the star In greasy should be 38 . 2 7 4 with soldiers round 38 . 3 and that's the answer and now that I know the star if I were asked OK how much he did the aluminum lose holiday the copper gained I go back and figure it out because I have a formula there perhaps and I can't figure out is that the algebraic sign was plus or minus In each case and that's how I would do it final miners Mitchell it is more blocks it's all about 2 blocks but I've got know that starting temperature reached blocked and that another capacity of each block I've got know the massive each block I just have another term here with the stars some other numbers and it's all the same it looks intimidating but it's all the same and no matter how many blocks you got it's always the same there's a lot of them you're going to use a computer To do this this long enough the most I called the final
temperature status the common the special temperature equilibrium that political defined identical the fire all yes I could say after the bloc's would work together rectangular savages what temperature will block initially but the answer is I have happened do temperature of at least 1 of block because dimension that number of combinations of part nautical Poland Poland but all kinds of things finally arrived at the temperature 1 loss on the final day of the group that you know to out otherwise can't figure it is if you have a really cold 1 and really hot on the American Center temperature as well what they just started at that temperature and it went nowhere that could be a solution to the Iraq was at the start I'm I'm going to have to know the texture of 1 of the block OK
calorie images is the business of measuring gallery had interesting to me that they live calorie content on food and then U.S. demand for the woman in the street and they have no idea what calories here is the spirit that Gallery in Manhattan this the amount the it takes of 1 gram of water 1 degree Celsius but calorie and who is a Telegraph Kennedy this column for gallery of food but it's actually killed him so if you 500 kcal today the operator can you 10 million jewel that is a lot of the machine that could do that and that's why no matter how much you exercise in view of the poorly or unwisely you're going to hurt you go on his house because that's then there's no way if you run a marathon flat out you lose 1 of you know less than a pound of flesh and therefore you you know if you run slowly it's going to be 35 miles so if you want to have that's 35 miles you go and then I and usually the 35 miles last time I checked the 2nd people in the state but there are some who think they think the need much more than they did because now they're not only 180 photosphere tired and hungry than in defenses a really pretty low and then if there's a Snickers bars around you go wild you have to be
careful well however the calorie values on food are also a little bit suspect because if we didn't burn food unit in the world and help but it won't be the same as if we needed it what exactly the same because for example if the food has fight the cellulose in Bonn gallery the will burn and produce the but because our bodies and metabolites selling for us it's 0 the agency cellulose there is still a pretty full but there's no calorie content and if you keep eating cellulose and nothing else to just drop dead and therefore they have to try to block out how much fibers in there how much stuff is undigested ball the other thing is that if you eat certain kinds of molecules your body may elect not to burn them at all Of if you're short of a certain amino acid a you economy last year .period doesn't burn and say Yeah I was just for program and the firm instead elects to use it to synthesize new protein therefore it because it gets much more complicated then you think sometimes to figure out what's going to happen but even if he mentioned calorie moderates really tricky because he can always he can get it from any queries have ever so terrible With the account for the big mistakes have been made by measuring reactions and not being careful enough to ensure that no he got away the calorie and the itself usually has a carefully calibrated capacity and then give the measure temperature change delta T the neck and be converted into jewels of that you produced by running the reaction let's have a look
let's Bronson magnesium don't ever burned magnesium because you cannot put out once again it's going it's extremely difficult firms extremely hot and bright the and it's extremely difficult to out but suppose we put a small amount 10th of a grand about of solid magnesium and we burn it in oxygen In a constant volume bond calorie the and that the calories and other has the capacity of 3 thousand 24 jewels Per degrees C. if we measured the temperature rise and I don't know how they got 4 digits but let's go with if the temperature rises 1 . 1 2 6 degrees Celsius then calculated heat given off in the reaction jewels for more you can already see 1 problem when you're doing this where he met the what if you have 3 temperature gages and there are many homages slightly different which 1 10 40 and and so In gets tricky because you have to be able to mix things fast and get the heat equilibrate everywhere so you don't have any hot or cold spots OK at the constant volume he will discolor use of the is given by the heat capacity of the bomb tolerant and that the change in temperature therefore I note he that was produced its 34 0 5 . 0 2 4 2 0 I don't believe all those digits of course but that's an intermediate result I work out at the mall amassed by looking at out of magnesium is 24 . 3 1 brand all and therefore I have 34 0 5 jewels her . 1 3 7 5 grand diverted to kill a jewel converted to malls and I end up with 600 killer jewels from all well I had a
look and I looked up the
and help the formation of magnesium oxide and it's minus 600 there 1 . 2 4 killer jewels from all which is pretty close Of course the antelope the refers to constant and this this Bond Keller and there was done a constant falling which is slightly different we might get a more accurate answer by using them a bit more magnesium and getting a slightly larger temperature change but we should never let the calorie Amador change temperature lot because the heat capacity of the calorie matter will be temperature and In a filing changed too much I may not know what it is anymore unless I have an equation for how did he capacity varies with temperature when you have gas is involved the constant pressure Moeller the capacity is larger than the constant volume the capacity because if I hit something of a constant pressure and the gap it's a constant pressure it always expense and therefore doesn't heat up this month so it's the best tired because instead of just sitting there and going out and temperature like crazy it expands a little bit and that it has to work to do that attitude comes from somewhere and so it's not going to stop and therefore in more advanced courses you'll see that the constant pressure molar heat capacity of the gas is equal to the constant volume already capacity plus just aghast constant which comes from the
vehicles an hour basically OK here however
case studies these guys are going to live in Greece out of the economic environment that is safe and they are raising money for this project that is going to revolutionize power supply here's the thing they're proposing to sell thermal power supplies and you can use them for whatever you want you can beat you boil water you can generate electricity and they tell you what they're using the ingredients they use a high-pressure hydrogen and powdered nickel the 1st thing I would do is look up whether the formation of nickel hydride is because that might explain the that the but the other thing is going to be very careful about this that if you go out the middle man the violence if you let me feel kindly New Lenox you will get an actual government reacted like crazy and the remainder in all kinds of excess heat and you get really excited you say I've got this round of power supply way more than right and here's what they think they've done they claimed to have rediscovered low-energy nuclear fusion this is the kind of nuclear fusion that occurs only in the center of the sun or H-bomb and they in there literature say that that's what they think is going on and that's why the power supplies are so great and because they handed all the intellectual property they're against sell worldwide and they're going to make a killing and what they would like you to do is give them money so that they can get off the ground because their starter and my question you is whether or not you should invest because of course a lot of startups don't pan out and you lose your money the guys working there that paid and sometimes right before they go bankrupt they pay themselves a lot like they did at Lehman Brothers but my
question is could it be possible but we mustn't just dismiss it out of hand because it seems outlandish so we have to ask could be possible but they are seeing nuclear fusion In this divide well let's let's look at their literature here's here's
the description this is freely available on the website of the guys doing anything to wrong but anyway they show you this little picture this is the preindustrial prototype and they comprise single and multiple reactor reactors so they use the R word configurations using nickel and hydrogen in Mexico's Derek reaction reduced thermal energy and kilowatt range provided safe and stable prices my question is how does it work they have the answer it is got the down here type of equipment and according to the class electric appliance boiler thermal source chemically assisted low-energy nuclear reactions they just like that in there that's easier to see the very chemically assisted low-energy nuclear reaction the 1st thing you say
is you have any nuclear physicists on your scientific advisory board note Have you measured a gamma rays coming out of this because usually when you have nuclear reactions that's 1 of the sites on why do you think it's doing because we looked at it after we ran and the surface was really rugged and there were all these defects and look like it's been blown out so here is my conclusion on that investment unless they
prove that that's what they're doing this is just a way to lose a ton of money but this is just like the power enhancer then but is more sophisticated because it will produce thermal energy because nickel and hydrogen will react and finally got oxygen and on the sly on the other and then they come back and then they put another tank of hydrogen and the recharge touted nickel but the question is how much energy does it take to to make the proper medical and the tanker fire what will
probably find out that takes a lot more than what you're getting out and their discharge you nominal led to to recharge at once vital thing and then probably
won't work both say they might be able to to prove that the good luck here's my warning many many schemes sounds plausible member Alexander Pope a little learning is a dangerous thing James deeper touched not the parents bring their shallow drafts and toxic in the brain while drinking largely sober again but you're an engineer and you understand the jargon and you don't understand that this is probably impossible you might think it's a good adventure you might put some money sometimes these things turn out to be correct but only if you let somebody independently verify and sometimes very surprising things do turn out to be true and other things that seem self-evident to most people turn out to be false that's why we've got signed the separate the wheat from the chaff and in every case we've got to do 3 things we've got a repeat the experiment not the same guy a different land they repeat the experiment they get the same result it's repeatable 2nd we looked for clues as to what's happening if I'm getting a nuclear reaction I looked for neutron silent for gamma rays to file see any of those I don't believe it In 3rd we never let anything except whatever the evidence way if we don't have any evidence for something when we got our default is to be skeptical we don't believe things without evidence because that way madness lies I want you believe anything without evidence American just tax whatever else I want so that police and I extract money from you or do whatever you highlight so the defaulters this year I'm sure you don't believe it what we're
going to do next Tuesday it is where :colon some practice problem for the final and a little bit of Chapter 18 and then Tuesday after that we're going to have a say in the next week we're going to you practice practice practice were ahead slightly in the world