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Lec 1. General Course Information & Properties of Gas.


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Title Lec 1. General Course Information & Properties of Gas.
Title of Series Chemistry 1B: General Chemistry
Part Number 01
Number of Parts 18
Author Shaka, A.J.
License CC Attribution - ShareAlike 3.0 Unported:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal and non-commercial purpose as long as the work is attributed to the author in the manner specified by the author or licensor and the work or content is shared also in adapted form only under the conditions of this license.
DOI 10.5446/19428
Publisher University of California Irvine (UCI)
Release Date 2012
Language English

Content Metadata

Subject Area Chemistry
Abstract UCI Chem 1B General Chemistry (Spring 2012) Lec 01. General Chemistry -- General Course Information & Properties of Gases -- 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.
1 incident that you do problems on the chance to get the right answer without knowing what the right answer it and therefore if you study by always a prominent saying :colon
wonder what the answer is quickly you won't be able to do the exam because that's exactly the point at which you have to know what you're doing so that point there's where you want focus on the protest the American it is an exam and see how you do and afterward straight years and and fueled on the hot I do agree on is that and so forth thank you very much better results excuse me there seems to be a little bit slower so
this lecture has a title that's because were filming it and then you know what the title of the lecture 1st you don't have to come to except
on exam day midterms hours on Tuesday and we will not start the mid-term right at the beginning of class will start about 20 minutes and make sure we can hand out exams have everybody seated that separates said think so you have sold time to do it all exams accumulative anything we say at the beginning we can ask later not just on little snippets of the material we have a website please don't send e-mail if it's important asked me in person I'll be there every Monday I'll be here every day after class for a little bit it's important just ask if you get 500 e-mails you just can't deal with any of them especially if the miners demands begins today the assignments not yet posted however it will be soon and then as I say they'll be a few problems due tomorrow and you can see the we're going to have to cover Chapter 5 because the instructors last term Herndon coverage for which is gasses and we want to make sure that everybody has covered chapter 5 and step-sister "quotation mark and so we're going to have to step on a little bit therefore I try to keep up with the move pretty quickly compared to maybe some other areas the book you
can use the book or you can just do the problems of the back of the book to discuss them in the discussion section you can read the book avidly or you can not bother reading the book at all and read something else each book has its strengths and weaknesses and they are all good in every chapter so use your own judgment great this percentage 20 per cent for the online homework 20 per cent for the 1st midterm .period preserve the 2nd of 40 per cent for the final no curves if you get more than 90 per cent .period you have a name and then we were down 25 point increments from there philosophically I'm against occurred here occurs treating you like a random variable I give you more credence than that on a curve make somebody else's poor performance speak for your good performance which is not the same thing the character furthermore encourages people to not elaborate and help each other and that's a very poor model for how you have to act in a real job to get anything done but for those reasons I don't like her the other thing is a curve is like saying I'm the fastest miler in
town the 1st thing people say is what your time what's the objective measure of your performance right they don't know how big the I'm the best in the Mac class so what who knows who was in the class we like to have an objective standard and that we can say clearly you're above that stance much easier OK
here's a practice problems shouted out there are so somebody has some How did you do that you don't know right not exactly it's kind of hard to explain you play around and then you get something that seems to make sense in many lock onto it and then you checked against your vocabulary and you say high I can make neurons a couple of things can go wrong you can give up when you're trying to rearrange it or you may not know the word neurons so you have to have a sufficiently good vocabulary in science we can't do any of the problem and then you have to be willing to play around you can't just assume that every problem is applied and China many important problems require sort of creative inspiration you have to
try things you can't be afraid of the problem you have to play around with it and think about it and then you may say discover some way to do it and not surprisingly chemistry is pretty much just like this word jumble because In chemistry where rearranging the letters and things and making new things and then we call the new compounds and we take lines and we suddenly rearrange them and then we say Hey that's new Robert and so forth and it could be the same thing in order to see how to rearrange it you have to play around with you can't just try to memorize all the answers to all the possible jumbled words I give you that's a very poor OK gasses well gasses are extremely
simple there is disorder this order and for that reason no living things that I know of anywhere is a aghast and the reason why no living thing is gasses because itar-tass can't store any information and living things need to store information so condensed phases can store information in particular the molecule DNA which can make copies of itself sort of a chemical curiosity took over the entire planet the elsewhere and Indiana came along and then the American made copies of itself and other molecules can and for that reason we got more and more and more and more expedient Over time inevitably this from that 1 factor no big living thing is a solid because if you're a big living things India is solid you can't move and that's something comes along Interstate you for lunch like a pack crows so if you were a big living thing is a solid you would last long viruses tho a very tiny crystals on living things and they can float around liquid so they can't for living things fluid were fluid were held together a lot of hydrogen bond the Giants so strongly which people who ride around on motorcycles don't seem to understand you are a
franchise and if you have a mishap at high speed that's it OK pressure force per
unit area you can get high pressure by having a big or by having a small area you see the magician where there have
been a rack and nails put on their chest I got so many e-mails that looks really dangerous and that someday guy gets on honorary puts some heavy on and everybody calls and Brett but you will never see the magician with 1 name right over the restful because then you put some heavy on images punches right through to the floor and that's the end of the month magician as of it looks impressive but a lot of nails but in fact it's making the area big so it's not present at all what's impressive is 1 scalpel that's impressive so PSI
that's how the pump up your bicycle or your car and usually that's the SIG which is yes above the atmosphere because atmospheric pressure is 14 . 7 pounds per square inch that's just the way that the column of air above your head you want your tired to have positive pressure so you about and she is
just what gage would receive a cage the difference between atmospheric pressure from inside for water Yoni 33 feet that's why the go scuba diving you have to stop and then clearing your ears because if you have any air bubbles changing you'll feel pressure and from mercury
because mercury is extremely dance use mercury in a barometer because it makes a very compact device it's only 76 17 or 760 mm and a millimeter of mercury and old units called for after Torricelli's if you can get a unit and science named after him you've made
and 2nd best is to have a hybrid tea rose many OK SI unit is the Pascal which is a very when United's hardly impressed at all 1
borrows 100 thousand pastels and 1 atmosphere is almost 1 book so but for our purposes the atmosphere in the bars are about the same they have to redo all the tables all the thermodynamic tables to standardize on 1 bar rather than 1 atmosphere and of course 1
atmospheres and nominal value because as we know the atmosphere pressure there we say we have a high-pressure regions there is pushing down getting people of other stuff away and so and set waltzes we're low-pressure regions and areas in Russian and usually that means there's a storm coming so if we see the pressure changing we may want to take some action and the pressure in the
center of the Earth is 350 Giga Pascal or about 350 thousand bar that's so high that it's very hard for us to get pressure like that in the last and that means it's very hard for us to understand all the reactions that might be going on in the center of Europe
because we we have trouble simulating them in the laboratory we can after a certain extent but there could be big things going on in the center of the earth that we may just not be able to understand completely because we don't know all the chemistry occurring and the center of the
sun it is about a billion baht and that is a very alien environment 10 million degrees a billion atmosphere pressure OK
Sir Robert Boyle neither
studied the behavior of gasses at a constant temperature In the thermostat a thermostat in those days was some big thing with thermal mass usually it was a bunch of ice and water so it would be a 0 Celsius the reason why you like ice and water is because as long as there's some ice there you know it's said 0 Celsius and as long as there's some water there as long as not all the ice is frozen solid you know it's an 0 Celsius so it's a nice day nowadays
a thermostat people think of as electronic device which uses a feedback loop to control the temperature actively in or but this was a passive devices in those days so while studied theirs
and he found that if you double the pressure which he could do With a device like a piston and just put 2 weights on it and he could tell the weights with the same by balancing the put onto each so that the volume like the hat and I think that I half as much weight the volume doubled they're are not and so he concluded that at a constant temperature and with constant amount of material you can have a lead but to be very careful gasses if you have a leak you roll experiment shock we have no leak and keep
the temperature constant then the product of the pressure times the volume is some constant and furthermore doesn't depend too much on what kind of gasses makes interest
which of these plots you think represents Boyle's shouted out when it whenever never you them who thinks it's a who thanks who thinks that see if you have the Saudi Arabia Han take it way
up there the totally wrong you'll remember the rest of your life and that's the important thing not to be right the 1st time but to remember it what's right
but the some people think is well OK how are we going to do it the way I would do it is I'm going to figure out I can measure the pressure times of all and I'm
just going to draw the squares here and I see that when this is 1 that has to go when as a student history but this is 1 students 2 times 3 that's not constant 1 6 the other this 1 is too but then it's 1 times for that's not constant this 1 however when it wants to do 1 it's Stewart's 1 that 1 word and this 1 wants it's 1 of 3 in 1 of 3 1 so c and they appeared the ones but
satisfies law is
boils locker at no it's only approximately correct it's going to be correct under the serpent under the conditions with with boils laboratory it's not going to be correct in the center of the sun or some other conditions needed study because he never would have come up with Boyle's law if he had studied all those things part of science and try to simplify things so that you can get something done if you just say Gee gasses so complicated they have all these different values the problem is it's hard to make any progress so you make an approximation you say under most circumstances if a reasonable but the behave pretty much like this and I have to be prepared for a little bit of give and take I can interpret these things literally for example at
very high pressures I guess will liquefy I want to make a liquid liquids are in compressible I need squeeze on a more they don't
change volumes at least not much so in that case the pressure's going up but the volume staying the same well it's not going to be a constant 1 of the same number the other 1 keeps increasing he said pressure confluence of constant so what's it liquefies but constant won't be a constant it'll change so PBA will deviate whenever the pressure sufficiently high the constant K whatever it is will increase wire condensed phases in compressible there in principle because once you have a condensed face a solid or liquid liquids a more useful however the Adams began to touch and their electron clouds stock
overlap and then there's a lot of propulsion and then as you try to squeeze those in there are huge electrical forces fighting you and they're very powerful forces so you can't win very very hard to squeeze down on some and that's a cost the principal of a hydraulic jack if you
take your car into the show they put it on a the punch of button and the car magically goes up like a magic carpet how'd they do that well easy they just basically equalize the pressure so I have a long thin thing here which in this diagram just simplified and I have all weighed about 100 100 pounds on a square inch so I have a 100 years side With this way and then out died this into the air and then over here I have a big fat guy because as
you know when you see the car go up there is this big steel thing that comes out right it's not tiny it's a big wide and so if I'm willing to go down here
100 inches and this area is 100 square inches then I can raise 10 thousand pounds 1 inch because the 10 thousand pounds distributed over 100 square inches is 100 PSI invite got this down 100 times as far I can bring this up 1 inch and so what I do is I get a pump over here and I just pop on a boom-boom will boom boom injecting more and more liquid not too high pressure and then slowly the current and I have to have all these pipes and things able the whole 100
PSI but nothing more than that and it's very nicely controls that's a way use fluent do work it's a great invention used everywhere elevators you name OK while the
Englishman Boyle was busy studying pressure and volume John Charles in France I was busy studying volume and temperature and what he was doing was making sure that the pressure was constant so he could have a cylinder the constant amount of pressure and could change following and change the temperature and found that the volume was proportional to the temperature and so pipeline volume versus temperature I get a straight line of course I can't make the temperature too low because then I get a liquid and in 1848 Lord Kelvin as whom we named the tepid absolute temperature scale he realized that the lowest temperature attainable would be when the gas appeared to have 0 volume without the gas have negative volume well with that we take a bunch
gasses and at temperatures you can access you measure the change in volume and then you got a straight line and then you got that straight line and you extrapolated the when the volume would be 0 and what you signed if you do that
is that they all converge on 1 point you have to be careful how do the experiment this year sloppy they'll be all over the place but if you're good experimentalist measures temperature accurately you ensure that the temperature everywhere in the gas is the same because many different momentarily in different places especially if you're changing it in the experiment yet be patient and wait for it to come to the full temperature then he thought the things and there you go there appears to be some point there which the gas and that would be a special .period we know that no real gas will have 0 volume but still that seems to be a special .period that's as cold as we predicted aghast and possibly get and it turned out that this cold is anything but so we call that absolute 0 on the cold scale this is Charles La and if we know the volume at any temperature we can calculate can the divided by the and then we can calculate any other the
carefully note temperature we can predict the ball the same amount material and send pressure then we moved further south the
Godhra there were working with gasses because that's what they could work with that's a big afforded no and that's what they could understand you don't work with things that you him I have the technology to deal with in your lap that's still true today whatever that found was that if you double the massive began then the volume doubles if he keeps the pressure temperature that sounds pretty obvious
if I've got 1 kilogram of death and I have a certain volume makes perfect sense that 2 kilograms of gas would have twice the
volume it almost seems that how could it be anything other than that but sometimes if you if you have interactions it doesn't work for example if you double the number of employees at the company you don't necessarily double the output because of the employee's argue with each other or get confused and spend time talking
instead of working you get less done on the other hand if they work together and 1 person's extremely good there's no persons extremely good at that and they both do the jobs that are very good at the new productivity can be far higher then don't be much much much higher the mass of the gas
depends on the number of moles of yet and call a mold it's just a number that's all a hits a number it's the number of carbon atoms the way 12 grand so if we write this down we can say the volumes proportional to the number of moles and here we we understand we have enchanted temperature pressure we just added more moles of death OK if we put all these relationships together Nicholas French Italian now we can come up with a master equation :colon equation of state that will work for gasses only and only under the condition
that the scientists studied the gasses and found that their equations were not hundreds some other conditions and certainly not for a liquid or solid every
Starwood Boyle's law we write the times B is a constant we don't know what the consonant with its accounts that's for a fixed amount of material and 6 therefore we can put some functions of number of balls a function of temperature of America's their fixed and then the constant I called K Prime for this function of and time function of the times primers case Long as I don't change entity I don't know what the function but the other guys did change AT T so we can get the function of an F 1 and the function of TF too by using Charles Law and the guard Rose Law we can get them so if we're right in
this way and we stare at a while we say got wrote told us but if we 6 p and and these things don't change and this is supposed to be a constant other told us that volumes proportional to to the number of moles but that means the function and just air we put an ad and if we fix the number of moles and the pressure then Charles told us that the volume proportional to temperature but this is fixed this is fixed at a cost but proportional to temperature it must be that the function of temperature is just temperature T so it but those things on and historically the missing constant is not called K Prime it's called are the gas constant and so we write the is equal to NRT upon peak or make it scanned better he vehicles and arty and this is called an equation of state an ideal gas law when we speak of an ideal gas were speaking of something that will follow this equation no pressure
His forced area but that's also energies for volume because if I have news for for meters square I can make terminated Newton's Times meters for media here the pressure is on energy density like like another mass density so many grams per cubic centimeter Gold is more dance and water I can have energy density high-pressure things are energy debt that's what opponents it's a high-pressure thing that's trying to get out yeah and causes a lot of damage when it does so In the other chemical plant that has high-pressure part you have to be extremely careful that none of them suddenly give way unexpectedly or you have a real problem so key times the then energy density energy per unit volume times volume is just as units of soapy times the it is a measure of energy if somebody says I wanna store when power by compressing air into a giant cave on the grounds that we dug up so when the wind's blowing I'm going to run this compressor
that runs off the electricity the winner gets 2 2 2 2 2 2 on the pump air in there open does leak out and then later on the let the air come out and spend some generators at nite when the sun is shining 1 when a Lowell you can figure out how much energy they can store by the pressure they can put in that conference times the
volume of the camp and if that turns out to be bigger than the volume of the birth or something like that and that he is not gonna work or if the pressure is unduly high pumps work OK until you get up to extremely high pressure and then the pomp and pump in more that just like when you talk about you pump pump company history hard and quick the other side as units of energy to them because the equal and things that people have the same unit exactly the same not different units both energy exactly the same unit otherwise they aren't equal so are whatever it is has units of energy Her mole mold her Calvin because our times most times Kelvin is equal energy the SI unit is 8 . 3 1 4 4 etc. Jules for a mole but more common for doing gas problems involving pressure and volume is to use are leader atmosphere In which case is 1 0 2 8 0 5 7 leader atmosphere for more Her defeat Chelsea you have to be very
careful when you problems that you get units right you will not get the unit's right if you do not write them down let me repeat that you will not get the unit's right if you do not write them down and you will catch a mistake made either so always always always right the unit it seems like a real pain and tell you get and on an example of a vehicle which is what I'm going to give you when the units are wrong or they aren't listed the answer is 3 3 1 if I have to say and my answer is news your the I can't be asking what the unions small mistakes
cost big money and they cast these people their jobs 1990 Nasser lost 125 million dollar Mars orbiter because 1 engineering metric units while another used English unit and what needed to be the the unit the swearing
on freedom Milan 2 "quotation mark crane I think I was working and that no we've never worked in that area we've always worked in that facility right the units down they had a JPL doesn't care but this is a small mistake what they care is at 125 million dollar loss that makes them look terrible who did right down here Was it yeah yes sir you're gone cats how their work I hope you're going to be doing something important like the Mars orbiter but if you are you have to be careful that you don't make the mistake Everybody will make them anyway but try to to minimize them if you write the unit the other guys and all this this guys working in miles or something thank goodness they told me that they're in the stone ages but I'll converted to meters and then we will pass the ship OK now just like
whilst slot the ideal gas laws only approximately true nobody would believe it literally for all cases however as long as the conditions are too extreme worked pretty well so a good 1st 1st rough but a high-pressure pvs too these molecules or atoms begin to repel at low temperature PV might be too small because the molecules or atoms might stick together low-temperature we didn't do on leave we get water vapor condensing out of the year on the leaves of plants in the morning
temperatures dropped below the dew point In fact
at high and low temperatures if there really high and low the predictions are just always way off so was pretty bad at low temperatures and make condensing and high temperatures the gas may react decompose or I and II In the summer the senator's son there are no too bad all the electrons boiled
off there's just the nuclei and that electrons everywhere like 1 big mess it's 1 of plasma moralists is so we would expect that to work in the center of the sun but much like we cannot actually physically draw perfect
circle we can easily imagine what and that's the beauty of imagination is that you can imagine things
the impossible to realize real life but that's also the danger Everybody who entered the lottery imagined that they were going to win they didn't embattled that they were going to get hit by lightning 50 times this year even if that's the same likelihood because people have a tendency to Imagen good things being more likely than that that's human nature that some good it could happen if it's something that no why crashed my car now both you gotta work OK so we can imagine gasses that wouldn't exactly follow that and we just say
Well there's such a thing as an ideal gas there's no real gasses is really going to behave that way but but we can solve problems that we can use an ideal gasses imaginary
gas and we can ask what it would do in real things like if we had running an
air conditioner or something next question if we had a heat exchanger for example and the properties of an ideal gas tell us the following because when he contracted temperature to 0 the volume is 0 that means the particles have 0 volume that's hard to imagine how something as mad and 0 volume but anyway that's what we're saying and likewise because the gas always fills the whole container no matter how load temperature In never returns and liquid on board that means that the molecules have no attractive forces they don't tend to stick together all real molecules a little sticky they stick together if there small enough could gather when they crashed to the bottom when you get a whole bunch of dropped crashes to the vitamins a liquid condensers there are no sighs there's no repulsive forces and there's no attractive forces that's basically what an ideal gas acquaintances if there's a better
equation the vendor walls inflation much better modeling and then there are even better equations that chemical engineers use and then if you really have to know what the volume of a gas is supposed to be for something critical like a power plant there a steam tables you look up what the answer it because somebody an engineer measured and they know what pressure is at that temperature and what volume but
we can take into account that the gas cannot shrink to 0 by subtracting something on From like that
the vault the the volume of the liquid or solid lets guests and the thing we subtract off we multiplied by the number of malls because the volumes going to depend on the number of bowls We know that from other got Rose Law and we want the cost them in the table that we make up cannot depend on the amount of material we don't
have to say how many we we just wanna say for helium
this value is there now it makes sense the me Adams and molecule should have small values of the but now this is getting interesting because if we can determine B which is just measure gasses that anybody can do we can say something about how big the particles are what the volume is on an atomic so here this equation we have to have a
different value of the for every kind of gaps that's no big deal but a compiled some values now word to the wise I will never ever ever I expect you know the specific numerical values all data if you work with thanks a lot of you all know the all a massive sold or the oxidation states that chlorine can have section I was forced to do that as a kid I had to memorize where every element on the Periodic Table 1 honestly that's a complete waste of time if you're going to be a chemist you'll know where they are the ones you you and the ones you never use you will care where they are that's how that works if you are going to be a chemist you're cluttering up your head with all this nonsense you may as well just memorize everybody's phone number In this class if you're gonna call it doesn't make any sense so I will list data but don't spend a lot time writing down data because if I want you to do it on an exam of the view that date all right I'm not going to ask for a specific value and likewise about the values of the constant are how to convert Kelvin etc thanks not important "quotation mark helium we get 2 . 3 7 times their minus 2 that's
something like the molar volume of helium although we have to be careful guns seen on quite a bit later oxygen Hey that's interesting oxygen has a smaller value of the eons oxygen is 0 2 that's it spezialised kind of puffy maybe like a big cotton ball chlorine that is bigger benzene on and part intelligent chloride very far from an ideal gas this used to be used as a dry-cleaning solvent and is no good for
your liver the switched away from it to something else which unfortunately is also talked the PCB and the switch to something else than the supercritical CO O 2 who knows if you dry-cleaning blue jeans they never fail which is interesting legislative branch banking new all the time I know that because there was 1 thing Utah also new we couldn't figure it out 7 dry-cleaned every time never changed color I'm interested now look at me
on me on this smaller then helium hot this doesn't make too much sense it might be true but I don't think it's true I think helium smaller than they are directly above on the periodic table so what we have to understand is that the way you get the value of B and a is you get a bunch of data you get the equations and you pick the values of a and B that give the best match the data over the range you've got you don't the data to be over 2 big arranged for
India bad you know on the 2 small Constantino pushed the parameters foreign so there's a lot don't be values are just the best I mentioned a but I think probably got ahead of myself the gasses also can attract how can they attract all
molecules track well let's take to add here
they are they're neutral they
have no electrical sources but they have some number end of electrons and then plus and positive nucleus is much heavier the electrons are like little naps and there are enough and they don't have any brain it just all do whatever they want so you can ask yourself what's the the probability that the electrons you're always all if the good thing all almost by 10
electrons as I was lying on its side and on that side and then if I cut it this way there's five-year fight here that this was by their invited there and you can start to see there is probably impossible at all times if the electrons and doing their own thing for that the and you would be right
is and so here's what happens instead we get charge fluctuations and we get a dipole what happened here was that we had a little bit the electrons skated over to the outside on the just further up the coast 2nd just a small amount and so that the took total Adam is neutral but this site is a little negatively charged and this site is a little positively chart I decided to stay that way people it has to happen and it keeps happening in all directions
was a very public on and on as opposing I nearby NI and electron and this guy and I'm really like and I negatively charged and there is a positive charge near me a heart of gold so there may get sucked over there but in that case we have to get an attractive for because this negative charge and this positive charge whole each other and it's going to constitute to start moving toward each other and then the spell may be broken fluctuating but still on
average many at nearby the other 1 will tend to move toward it and of course if they get bashed at top speed by some other freight train it just says for data so well still aghast but as we cool it down and they spend more time moving slowly and they spend more time close to each other like Idaho 1st you have dinner condensed into a liquid phase on the bottom of the container the same idea so we take into account the attraction and by reducing the pressure and
the way we do that this add an attractive feature that makes the pressure plus the attractive terms equal to the old pressure and that means that the
new pressure is lower and we expect the pressure degree lower for the following reasons if I against the pressure is basically began pushing out against the side of the container if the house yes attracted to to itself so it's making it smaller than the pressures last it's not pushing out as much as the gasket the atoms were telling each other sometime which they cannot then would push up unless the charge is there altered state we have to
add an attractive terminal we can see what it should something and then something that depends on how close the particles
are which is the number of moles per volume for the 1st guy and the number of moles per volume for the 2nd guy because we need to guys to get the 2 not 1 for the further the we needed 1 that following the 1 attraction we need to guys so it's worth density square and then that says are equations which together if I want you to deal with this equation on an exam and I will give it to you but it's pretty easy to
remember I remember a attraction and then be used for polls but I don't remember the I remember a for attractions end of story I always try
to remember the minimum I don't want another thing in there because of another thing and there you may get mixed up the
values of a for the attraction of tabulated and they make sense when we understand intermolecular forces let's look at the value because of a
for various materials I would expect this fall I would expect a small
Adam that has tight control of its electron it's like a little golf ball I would expect that it would have a small value of very because there wouldn't be any electrons moving around flopping all over the place I would expect a big a thanks with a lot of electron I would say that's very unlikely that the non-compete 50 50 all the time it's going to have a big value of it and so if I were given materials on an exam and the values of a and I were asked to write something intelligent
I could because I can't say Ohio look this high-value that means a century polarize Isobel what is high-value see this Adam occupies a slightly greater volume than that 1 sector could make stakeouts about atomic properties just from news that so again these are just for interest we don't care what the actual
numbers are helium 3 . 4 7 times 10 months to union leaders squared per bar are much more attractive while liquid helium is 4 . 2 Calvin it's extremely cold before liquefied argon is more like the temperature of liquid nitrogen and that's that reflected in this much larger attractive forces much easier to to liquefy are and this see not much of for four-point 2 ways still the the other guys and see
how they 1 . 3 8 so oxygen again is
smaller than seen on in terms of attraction and smaller In terms of apparent volume and then chlorine is much higher In a carbon tax is well it's almost 20 that's very very high cost carbon tax a liquid a room temperature the others are not and now for neon we see that the beyond which has more electrons than helium 2 versus 10 so it has a much higher attractive but 20
10 times higher anyway then the helium and so our
conclusion is that the neon nucleus control so stem electrons much less tightly and the helium nucleus controls its 2 electron and so it has a much larger value for the vendor walls constants for attractions it's OK now
solving for this year given
the other variables no problem but solving for on the if I said I Gas occupies 1 leader at 100 Celsius and 50 How many malls a gasoline there that's about all staff if you haven't tried that that'll be like near on you can stare at it a long time and that so if you haven't played around with it played around with the equation very dear friends it will be here and
you just disaster when you try to deal with likewise the restrictions a mathematician would tell you to expanded out and then write down the roots of the cubic equation because mathematicians like to do that believe it or not they love to do that the more difficult than that makes them feel good coffee tastes great and so on but this equation it's unbelievable but we solved quite a thrill sometimes but we usually don't want to solve it for every possible bawling we have an exempted were given the temperature and pressure and were at and 1 mole lets and we want another volume and we want do it efficiently we want 1 number not the totality overall solution In the end the
entire thing chemistry usually we only want 1 numerical value we don't want a full analytical solutions and so it's always crazy take a problem and make it harder and then sold and then get the answer but if you write down the rules for a giant equation which is for all possible values of unity it's much more complicated I'm just
sticking in the numbers and seeing what you get so never make a problem in chemistry or any other science more complex than the starting problem and then try to solve it unless it's already known and solve some complex problems are known In that case find usually not usually you've made it worse simplified the roots of acute Baker are
tedious and long you can write down as an exact solution there is an exact solution for recording by the time you get to 5 something weird happens there's no solution I can't write
it down at least not in all cases OK practice problem-free so we got our
dry-cleaning solvent what volume would you predict at 100 degrees Celsius and 1 atmosphere for 1 mole of carbon capture chloride if it is treated as a as an ideal gas Read follows exactly the equation be equals an as a matter of staff
read follows exactly the equation the flustered and square for certain calls on and on 10 this might be something that you might want figure out well for the ideal gas we just
used vehicles and not your PC and I see that it set 100 Celsius and I say right away what units always Calvin Lord
Kelvin always "quotation mark temperature it it's a beautiful day it's 294 Calvin yeah you're eccentric but you're never wrong but if you do chemistry problems in units other than Calvin you are wrong and you get killed the futures substantive Fahrenheit or some other hope units into these equations without thinking about it's not enough to write agreed for something because degrees now in actual fact when you solve a problem the guy says What is
this something in Fahrenheit and they don't know any sign a new converted Calvin you solve it and then you don't speak to them and Jardins don't say what is and tell you converted back to Fahrenheit or bushels of corn or dollars and
cents and tell me after they wanna know that's what you do don't leave it in your intermediary language of side effects and from b this is supposed to be right should have been a capital Hill that's both leaders but yeah you're right a lot of making a capital and also it's clear
OK and so when I get is 30 . 6 and then I put see output parenthesis around it that's like China's special Non-Aligned until you don't have to do it but some people will notice that means that I'm putting that
but that is is uncertain so I'm going calculate further I'm gonna use 30 . 6 2 I'm not going around 230 . 6 and then go further however I don't really believe that too is significant that measured the the other things well enough to know if that's 2 or 1 5 that's my answer answers this is always the safest way to quote that you look up the constants in nest in the table on every continent be like you . 9 9 7 3 5 so that for the vendor walls
Gaskins I looked up and now I do have a capital L 19 . 9 6 liters squared atmosphere all squared for a attraction . 1 3 8 leaders from all for the volume and
honest 1 mole exactly the where the problem was worded so we have this equation no the 1st thing you do is you can put all the numbers you know right there is no
sense in even wasting any time simplifying this equation symbolically by moving letters around the playing around all it's going to happen there is that if you make an algebraic aerial start out with the wrong answer from the get but in all the numbers you know and then continue no but all the numbers I know what RT is that was a 30 . 6 2 from before and so I I write the equation as a numerical equations With 1 unknown and my claim we solve this by guessing yes simple or if calculator will do you can turn on calculus I'll accept that on an exam of detail
manner but if you calculate does it in your calculator does it wrong year on that 125 million dollars space on with new going down with so you better make sure that it doesn't rise but here's what I'm going to I'm gonna set up I'm gonna call
this numerical thing with be some function of the on the right hand side was Artie was 30 . 6 2 and I'm a plug-in values of the and I set up a table you can do this on a spreadsheet easily starts to and really organizes your thoughts to set up a table don't scribble things of random angles on the paper well I'm gonna 1st guess it's an ideal gas an ideal gas has a volume of 13 . 6 2 leaders I shove and
30 . 6 squared and 13 . 6 2 here and I turn the handle and outcomes 31 . 1 3
now I lost 30 . 6 2 and then I have a comment I always have a comment because if I come back 6 months later and look at this work the comment is going to be important to me sometimes will jog my memory it'll will put everything in context all remember what the whole problem was about and while I was doing fighter said numbers and things sometimes I can't remember what I'm doing and I have to start over well OK it's to bed so I guess I should lower the volume How much wealth it was but half a liter to well I lower the 2nd round number so I went for 30 . 62 to 38 . 0 0 and now it's still about half a liter to bed but 6 excuse me yet half a liter bigger than what I put in but . 1 liters less than what I I've not so now I said Well gee I guess go away by . 1 leader and been there you get the right answer it's amazing but if you get good at it
rarely takes more than 3 or 4 rare because you'll see what values you're
getting your home and also a few contraband but I have 30 points 16 . 5 to 50 I don't accept the 50 I go back and do the calculation again I probably get around but but if I'm doing some method where I only do it once and I hit the wrong button I just get this bogus answer and then I just write it down thank you so wear sort lucky to arrive at the answer quite that quickly but even 10 guesses is much easier then using the roots of the Cuban and here's my comment that and then .period if year calculator will do it I'm fine with your calculator little graft the function and you can find words equal no problem do it that way you won't need to have a
high-powered calculated to do well on this course but if you have 1 and you know how to use it uses are not shackle you with your hands behind your back but you don't have to however check your answers please put it back in the event's on an exam that will make it to the author
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