all kinds of other things so we're recording this session so that we can post it and if you want to review it later you can so we're going to be working on the active learning problems but first i kind of want to ask you if you have any general questions you need to ask me i hope everything is going well for you in the class and that you're getting adjusted to all the different systems that we use i hope the lab is going well and everything questions like before we get started um you can unmute yourselves to speak directly with me or you can type into the chat if you're feeling that you don't want to talk on camera so any questions about anything none okay so i assume everything's going well well thank you for coming to active learning we're going to be solving some ph problems but again we're not confining the questions to only ph problems if you have other questions about anything in the course or any other content i'm happy to help you so i will be posting the solutions to this up um in web courses so the first ph problem is a simple ph problem about the concentration of hydrogen ions if the concentration of hydrogen ions is 0.01 what is the ph in a the poh and b and the concentration of hydroxide ions if you haven't seen it yet these problems are posted without the answers right now in web courses in the module and i will be posting the answers as well so let's work on this problem by using the whiteboard kind of flip back and forth here because my ipad is acting up all right so ph we want to know ph ph is equal to negative 1 times the log of the concentration of hydrogen ions so that's the ph formula and why are we going to use the ph formula because they give us the concentration of hydrogen ions is 1 times 10 that's a 10 to the negative 2. that was 0.01 as a decimal right so this really means times questions yet so we're selecting the ph equation because ph is related to acid and acid means hydrogen ions are protons we would not want to select the plh equation because that's related to hydroxide or base okay so ph equals negative one this whole expression the log of the concentration of hydrogen ions if logs were not your friend before the good news is in this class we're doing simple ph problems we're always in base 10. so because here's the base this is the base 10 this is the exponent negative 2. you take the exponent with its sign and pull it down this whole expression the log of the concentration of hydrogen ions is substituted by minus 2. so ph equals positive 2. or again if you have some experience with this you say i'm 2 units behind the decimal point that means i'm 10 to the negative 2 ph is positive 2 because it's the opposite question question yeah what chapters ph problems ph problems are in chapter three so chapter three starts out with water properties of water and then it launches into ph um they don't do a good job of explaining ph problems too much that's why we're doing this with you to have a video and make sure you got it other questions so did this kind of make sense this was part a of the first problem so this was a and then part b what is the poh well there's a second equation and again it's important for you to know these equations because you'll use them during the exam and the quiz is ph plus poh equals 14. again poh is the base or hydroxide concentration ph is the acid or h plus concentration all together the whole scale adds up to 14. so if we know that ph is 2 then poh is 14 minus 2 [Music] which is 12. that's a one so the p e o h and b is twelve questions yet everybody's really quiet okay no questions so in part c it asks what is the concentration of hydroxide ions okay well we know that the poh is 12 that we know we just calculated that question yes can you explain how you got the log to go away on part a yes so we're in the base 10 and the number we're working with is 10 to the negative 2. so because we're in the base 10 and we're always going to be in the base 10 when we're doing ph and poh you can literally just take with its sine and this whole thing the log of the concentration of hydrogen ions is substituted with the exponent from the base so you just pull the exponent down with its sign and substitute it did that answer that question yes thank you okay so in c we said again the concentration of hydroxide ions what is it well the poh is 12. so we're in the base 10. so what we know is our base is always 10 concentration numbers are going to be 10 to some negative exponent what is that exponent going to be it's going to be negative 12 okay you could work this out by saying poh is 12. 12 equals negative 1 times the log [Music] of the concentration of the base okay so basically this becomes 12 is negative 1 times what 12 is negative 1 times negative 12. that's why the concentration is represented by 10 to the negative 12. so as a general rule ph or poh is always going to be a positive whole number in biology you are not going to see zero ph often i think i might have given you one problem like that but um it doesn't living systems don't do that because they'll die it's too strong so ph of poh is going to be you're going to see a number between 1 and 14. yeah okay um excuse me i was just wondering what um lesson is the vanderwaal and i'm sorry to like jump in the middle of your teaching no problem vanderwaal it's good um vanderwaals is in chapter two right it's in chapter two but you said to read about it more in your powerpoint and like lecture yeah so you just wanna read a little bit about it in the chapter but i've you know pretty much what we're gonna stick with for vanderwaals for the test it's going to be it's in nonpolar molecules and it's a weak attraction and if you know that you're good oh okay that's fine that's perfect then and um i have been listening to your powerpoints more than i've been reading um that's okay that's fine watch the the order that you want to do this in is basically you wanna you know listen to the the powerpoint lecture to the lectures you want to do the realization and then you want to like read in the book for anything you might not understand out of all that okay it's any okay like totally overboard until chapter 12. like they treat you like you've had biochemistry already yes because i tried reading it and i was like wait she didn't go over this in the powerpoint like in chapter two of the book they start talking about sp3 orbitals if you haven't had chemistry i saw that i saw that we're not going there i mean you know we're doing the basic stuff to get us to cells you know that's that's pretty much it yeah and i was okay perfect and also i was just wondering how these are like super quick questions i'm so sorry and then i was wondering how you can differentiate between polar and nonpolar bonds like when when the practice problems like on polar bonds um are polar covalent they're going to have partial charges they're unequal sharing and then non-polar covalent they don't have any charge at all they're not partial charge they're not an ionic is like full charge um so how would it be at like because there's a problem there's there was one like a practice problem and you asked like what's the name of the bond and like i knew it was covalent but i couldn't i can't tell you like i can't differentiate if it's polar covalent or nonpolar covalent yeah that's going to be an easy one so if it's there's going to be in biology right now there if if you see nitrogen with hydrogen or oxygen with hydrogen that's polar covalent the if you see no with a hydrogen either of those it's polar covalent uh if you see two carbons it's they're equal those are pretty much what you're going to see oh oh perfect so so like the nitrogen oxygen's polar and then carbon is non-polar carbon decarbon is non-polar that's pretty much what you're going to see oh perfect okay that's great that those are all my questions thank you you're welcome you have a going okay so we were on part c um and that was concentration of hydroxide we figured that out and we said now generally ph or poh is going to be a positive whole number between 114 and biology there is zero in chemistry living things don't do that for very long if you see these brackets this is the symbol for concentration and chemistry if we're asking you concentration it'll be concentration of age concentration of o h so concentration of acid concentration of base this is going to be something the concentration is going to have the base of 10 and there's going to be some negative e for exponent right so if it's if we're asking you on a test or a quiz concentration you are looking for the answer that is 10 to the negative exponent or it could be in decimal form so let's say like 10 to the negative 2 is the answer it could be 0.01 oh that didn't turn out right 0.01 also so are you with me so far questions about what i'm saying right now so when you're looking for ph or poh you're looking for a positive whole number between 1 and 14 in biology one occasion you'll see a zero if i throw a problem in there um when you see the brackets you're looking for 10 to a negative exponent that's what the answer is going to be in that form or a decimal with something behind the decimal place questions yet okay so that was number one so we're gonna go back to it should just not flip me out like that but it does okay number two concentration of hydroxide so this time we're working with base it's 10 to the negative 4. what is the ph b what is the poh and see what is the concentration of hydrogen ions which is different we're given hydroxide and now we're asking for hydrogen ions so let's go to the whiteboard and do this one okay so we're gonna we have hydroxide so we have to use the poh equation because poh refers to base and hydroxide is base so poh equals negative one times the log of the concentration of the base that's a negative there we go that looks terrible okay and we've been given that the concentration of the base is one times ten to the negative four so in this whole expression right here what number are you going to substitute for the log of the concentration of hydroxide you tell me i'm not telling you is it negative four yes thank you okay so you take the exponent with its sign pull it down negative one times negative four so the poh is positive four that's part a questions about what we're doing that's a everybody good are we doing part a of number two we're doing part a of number two yes this is number two let me do that too okay so b what is the poh well we know we got poh what is the ph okay so we actually did this was actually b so i did them backwards because i had to figure i couldn't figure out acid without doing base first because they gave us this this is b this is a so poh plus ph is equal to 14. so in a we wanted the ph so what is the ph going to be we're going to say we have 14 ph units the poh was four the ph is ten okay are you with me did i confuse you questions you guys are good at this um i have a quick question yes so the document that you showed us at the beginning of the lecture is that going to be like a homework that's due or is that just like a review too so it's just you know this is all free practice so the you know all of the sheets we have up there all of the active learnings this is i don't want you to be stressed while you're doing this because you have to have practice to learn so it's all free practice it's not for a grade what happens is after you've done all this then at some point the quiz over chapters two three and four opens up and that is for a grade and then the exam opens up and that is for a grade over chapters two three and four cumulatively for the whole unit okay and then as far as like keeping up with the book as well as like watching the lectures if you mainly just watch the lectures and like participate in the reviews that you post do you think it'd be um satisfactory or do you think right now we're in the beginning chapter so for one through four if you understand what we're doing the book you you can kind of like just look at the book for increased explanation if you need something but once we get like to chapter 12 then we're going to use the book a lot more i mean it's not that you'll have to take a lot of notes because i've put a lot in the powerpoints but it explains more like right now in this chemistry stuff it's really not as helpful to you yeah okay thank you you're welcome any other questions so we have to do part c what is the concentration of hydrogen ions okay well if ph equals 10 and 10 is our base what is the concentration of hydrogen ions 10 to the negative 10 okay again you can work this out saying we know ph is 10. so ph is 10. you can actually use the ph equation or you can just flip it in your head 10 is a ph 10 is equal to negative 1 times the log of the concentration of hydrogen ions 10 is equal to negative 1 times that's an x let's try that again 10 is equal to negative 1 i'll use a dot times what negative 10 times negative 1 is positive 10. again in these equations this log of the concentration of whatever it is this is representing the negative exponent so this is the negative exponent of the base 10 that is the concentration of hydrogen ions questions problems i have a quick question um can you explain again how you decided to do the poh before the ph on this one yeah that's a really good question so the question said we were given so what i'm looking at is the given we were given concentration of o h minus we wrote it out as the word concentration is 10 to the negative four i can't use the ph equation because ph is related to acid and they haven't given me acid so i have to use the equation where o h is in there that's where i have to start that's how i decided what equation to use so then i said okay the concentration is negative 4 i'm going to substitute so how i decided was what was the given so you always look at am i given concentration of base concentration of acid ph and my given acid or base if you're given base you're either using poh or the poh equation if you're given acid you're using ph and the ph equation did that answer that question yeah so it's because it says hydroxide instead of hydrogen if it said hydrogen we would have started with ph is equal to one times the log of the concentration of hydrogen ions yeah that makes sense i just didn't pick up on that well thank you it's kind of confusing because there's a lot going on i know thank you you're welcome washington uh can you explain how you got negative 10 and why it's not positive 10. okay so i let me i'm going to write it out down here so i'm using the equation now ph equals negative 1 times the log of the concentration of hydrogen ions and now i'm going to substitute what am i given what do i know i know because we calculated that ph is 10. so i'm going to put 10 that's a 10 not lo is equal to negative 1 times what right what times negative 1 is positive 10 negative 10 times negative 1 equals positive 10 and that's the ph so this is my exponent the log of the concentration of hydrogen ions that's the exponent of the base we're in base 10 negative 10 is the exponent just like here when we had poh we said the concentration of the base is 10 to the negative 4. the log of the concentration of base takes the exponent with its sign put it down did that answer that question other questions it did thank you okay okay so that was two so can we move on to the next or are there more questions about these so yeah you have to look at the given whatever you're given you need to start with that and work your way back and look out because on a test sometimes we'll give you the opposite thing first so that you're cranking through all different steps to get to the answer so you know when you take the test you want to like not have stayed up all night you want to be really awake and you want to say what am i given i'm given this okay i need to calculate with this equation first okay so next is let's go back to the questions it keeps flipping that off that's why i want my ipad because my ipad won't do that i'm gonna have to talk to computer services okay so this is one where we just ask a straight up question if if on the ph poh scale is 14 a strong base on the poh scale not the ph scale poh and ph are different scales and in the answers which i'm going to post for this i show that to you so what do you think how many people vote for true how many people vote for false this is where it would be great to have clickers but i really didn't want to ask you to buy clickers to do this like once or twice a week or a month or whatever because that would have just been ridiculous so um poh scale 14 is a strong base true or false we'll tell you what you think tell me what you think and then we'll go look at you know do the answer and don't be afraid to make mistakes because that's how you learn that's how we all learn you know like i can tell you i like you know had like a 4.0 and then i went into organic chemistry which is legendarily horrible and i was studying for 20 hours for the test and basically i went to take the test and i thought this is not going well but what did i know i had never even gotten a c before um and then i got a d that was two points from an f and so i went to the teacher and i was like obviously i'm not studying this right and then i figured out how to study it in every subject you study a little bit differently college is about learning how you learn actually and then i got using all the rest of it and ended up with an a in the class but it was scary so i know what that's like it's like you think oh no my life is flashing in front of my eyes what if i flunk the next test so i can relate to this they said false and uh really good that is true because um and for people that are being really quiet thinking what's going on i'm just gonna for a second okay so there's the ph scale and then there's the poh scale and in the answers to this that i post i'm gonna post these scales next to each other as a comparison in an actual photo so you can see it if you have ph like zero which is a super strong acid right the poh is 14. so a poh of 14 is actually a very strong acid okay and by the time you get to pa poh0 that's a really strong base so these scales are like opposite each other and we're going to show you this in the answers that we post there's like actually a document that's a picture that you can see so any questions is everybody understanding that concept okay good so you guys must have had a fair amount of chemistry already which is good okay so number four if the poh is five what is the ph so you can either just tell me the answer you can type the answer in the chat and then we'll see nine yep right because ph plus poh has to equal 14. so 5 plus 9 equals 14. perfect okay questions about these things if you're not understanding don't be shy there you know you can and if if you're too shy to even type questions in the chat you can always email me and i will talk with you about it over email so here comes number five this is gonna change everything that you already know right now so this is a problem you need to be able to identify the different pipes types of problems on a test so as we just said you look at what you're given here you're given two numbers in the problem yesterday the ph in your pool was six so you added some ph balancer today when you re-measured the ph was 11. this is the first time in any of these problems that you see two ph's or two pohs so you see two numbers and then we ask what is the change in the hydrogen ion concentration this word change and these two numbers indicate you are in a type of problem that is special and different it's called a ph comparison problem so this you would identify from the two numbers and the word change in what is the change in that's a typo um you would identify this as a ph comparison problem ph comparison problems okay if you're asleep wake up now we'll always have positive exponents this is changing everything we've just told you so you have to be able to identify this problem so you don't get mixed up so if you see two numbers in the word change you are in a ph or poh comparison problem and the exponents will always be positive so let's work on this problem go into the whiteboard let's clear this okay so we are going from six to seven up to eight and we're going to keep going nine ten and eleven and that's where we stop so we're going up the ph scale more acid is lower more base is higher so every time you go up the ph scale you go 10 to the positive 1. so between 6 and 7 10 to the positive one between seven and eight ten to the positive one between eight and nine ten to the positive one between nine and ten ten to the positive 1 between 10 and 11. so you have gone one two three four five this is where we get the 10 to the positive five it's an absolute value in between each number of the ph scale there is a 10 times concentration difference so we are going up the scale so at 6 to 7 we have decreased the amount of acid 10 times and at the same time we have increased the amount of base 10 times so you see what we're doing um this is the acid and base in any solution is like an equilibrium it's like you can only legally fit so many people in a car so if the acid goes down the base goes up if the acid goes up the base goes down it's like if you have a four-seat car and that's all the police will let you carry is four people like you can only ever have the same amount so it's all in equilibrium so questions about how we got 10 to the positive five it's not 10 to the negative 5 because that would mean there's 0.1 or a 10th in between each ph unit there is not a 10th in between each ph unit there is 10 times so we're getting more and more and more base so by the time we get to 11 we are 10 to the 5 times more base there's a higher hydroxide concentration and a lower acid concentration questions yet now is there a question yep uh i'm here because i i was at work um um i have a question i was doing um some ph problems and i think you have just uh about i think i have the same question that you have just i think describe it and i think it's 16 15 and 16. okay i can't see that suffering okay sorry and the ph in your pool yesterday was 12 you add acidifier you measure your pool water ph today and it is six so the at concentration was ten to the four positive okay we're going to do that we're going to let's finish this one and then we'll do that okay okay 12 to 6 he said right yeah this is yeah 12 to 6. okay so let's finish this one okay so we went up the ph scale so the acid is decreasing so you would answer the acid has decreased the ec decreased uh can i can which which one you're in what you're doing still doing problem number five from the application yeah thank you thank you so the acid has decreased 10 to the 5. the base we didn't ask you about the base but if we did the hydroxide concentration of the base has increased 10 to the positive 5. because they're in equilibrium what goes up must come down it's like the scales of justice does this make sense are there questions are there [Music] problems so everybody good okay now we're going to do this one this is a good one to do we're going backwards we're going from 12 to 11 to 10 2 9 2 8 2 7 2 6. what you can literally do is say i'm going you can subtract here you could have said literally i'm going from 11 i'm not just through 6 so i have 5 units and that's how you get the positive 5. here 12 to 6 6 units so here the concentration of the acid is increasing 10 to the positive six because six units ten to the one ten to the one ten to the one ten to the one ten to the one ten to the one six jumps one two three four five 6 and at the same time here the hydroxide or base is decreasing 10 to the six that looks so bad this is increase did that answer your question let's increase so increase and hydroxide decrease um i have a question and last time a sine didn't change it has to be positive this is what you explained last time yeah this this has to be positive because there is so this is a good example of even when you're going down the ph scale or up the ph scale if you go up or down there is an absolute value of a concentration change of 10 units so the concentration is not what's changing um in between each unit it is basically if you're going down you're going to more acid so in the second problem you're going you're getting more acid in the first problem you're getting more base because you're going up that's what the difference is okay so both are 10 to the 6 positive but the arrows were so um the errors so this one is acid is increasing and base is decreasing in this problem so how do we answer these questions like 10 to the 6 and on a test you would see um the h plus ions are increasing 10 to the six the h plus ions are decreasing 10 to the six the oh is increasing 10 to the six you would see it written out basically and you would have to pick whichever one is correct okay and once again the problem you were doing before that was number five number five on the active learning office hours practice sheet which is in web courses and the answers for that will be posted as soon as i get out of all the active office hours today part one right chapter three ph practice problems part one no this is active learning here let me let me okay okay um i don't wanna do that do this okay i'm gonna stop sharing good here it is so this is what we're doing right now this is called active learning office hours page problems it's posted as active learning office hours page okay and i just posted yesterday so you may not have seen it yet either no i didn't yeah and that's fine and i will be posting this video and then i'll post the answers to it so yeah okay that's fine because i'm not in the u.s i'm six hours ahead actually yeah okay yeah that's fine and and um that's why when guys when we do testing your tests and your quizzes will open up the day that we say that it's going to be open at 1201 am and they close at 11 59 pm so that anybody in a different time zone is able to access that when they're not asleep okay yeah so no problem questions about these ph problems um or about any other of the content that we're doing in unit number one which is chapters two three and four of course you probably are just getting to three now and you'll get to four on friday but questions about any of those things or about any of the things that are happening in the course that you might need help with everybody's good so okay so um you know yes question okay after this worksheet can you go over vendor walls yes so um van der waals forces are we're going to say between nonpolar molecules they're very weak and they help to hold nonpolar molecules together there are some other categories we're not going to go there on the test and it's due to unequal distribution of electrons so as the electron is orbiting where the electron the electron is negatively charged so where it is it blinks a little bit negative although it's not a real charged particle as far as the whole molecule goes and where the there is absence of the electron in the orbital of that time it's not blinking negative i mean so these little blinky attractions hold nonpolar molecules together if you understand that much you're doing good other questions about anything everybody's doing okay in the lab you're finding your lab orientation materials and you're you're getting into second life and everything is good you've been into the modules so you know when the quizzes are going to be and those are also in the syllabus which is posted question the vendor walls are between attractions of nonpolar and they have a slight negative charge okay so the van der waals are between nonpolar molecules and it's not a it's not actually a charge but it's the electro electrons naturally do have like are negatively charged and as they're orbiting they it kind of is a blinking attraction it's not that the whole molecule gets negative it's it's like a force when the electron is moving it blinks a little bit basically and that weak attraction holds some molecules together it's not like a partial charge it's not like a full charge it's just the movement of the electron um is doing it the electrons plural in some of them other questions i had a question so when i read the book i learned that there were like the london dispersion forces and the dipole dipole forces are you just talking about london dispersion because we're just talking about stackable it has coal dipole is polar and so we're just going to stick with nonpolar in our class because i don't want everybody to get confused between dipole-dipole and polar covalent because that'll be a disaster so okay so just don't worry about those what you'll see is when you see quiz questions it'll be very general between nonpolar molecules or whatever yeah and it'll save vendor walls it won't say dipole dipole you shouldn't see anything about dipole dipole at all yeah okay okay thank you you're welcome anybody else yeah so many of you have not even probably had chemistry yet or if you're in chemistry you're in your first week of chemistry so it's all like a lot right now any other questions about anything at all you said that when you have like the ph problems where you add the acidifier both answers are going to be positive right yeah so any of any number that you get that's an exponent is going to be positive because in between each of the numbers of the ph scale it's 10 to the positive 1 or 10 times which is positive numbers yeah okay thank you okay yeah and so i just want to like share with you that um there's more help that's been added and that is i i have it posted in the web courses modules you know zaren is your si leader and she will be running sessions well now john who is also amazing john is going to be your sarc leader there's virtually going to be no difference between these two things if we were in face to face sarc is in a different location than si but um basically because we're online they're all going to be in zoom i've posted the zoom links and the zoom links for zurin and john their sessions are permanent links that you can just keep hitting to get in john is going to be there every monday tuesday wednesday and thursday from 1 30 to 3 30 and um he is amazing he's really organized and his test reviews are legendary um he's been my he was in my class and got the highest grade that's ever been in my class um and he's been an si leader for like three or four years now i'm a sarc leader so you know basically you want to catch those sessions because they will be working through things with you it's extremely interactive um and it helps you so you just don't only want to catch a test review but you want to go as much as you can during the week to go over things and and get help there so that's posted in the modules it says john's sarc sessions and then i've also permanently posted zarin's si session she's also amazing um and so that there's more help there other questions so i have a quick question um is it true that on the ph scale um it gets more when you get more basic the hydrogen ions go up and then the hydroxide ions decrease okay so when you get more basic as the numbers get bigger so if you're going 10 11 12 13 14 up there um the hydroxide is increasing as the numbers are increasing and the hydrogen is decreasing as the numbers are increasing so at the lower numbers you have more hydrogen and the higher numbers you get more base so it becomes more hydroxide than hydrogen so hydrogen is a measure of acid h plus is a measure of acid and o h minus is a measure of b did that help okay thank you any other questions i'm gonna stop this year and acids and bases react to form water they do water and salts usually any other questions can you go over ph i'm starting chapter three and i kind of want a review before i start okay so we just did that actually so but we will go over ph really quick so ph is a measure of acidity so ph equals negative 1 times the log of the concentration of hydrogen ions concentration of hydrogen ions is a reflection of acid okay so if we say the concentration of hydrogen ions is ten to the negative three to find the ph you say negative one okay the fan's gonna ring times what that's a question mark [Music] call just from it off sorry so ph equals negative 1 times what this whole expression the log of the concentration of hydrogen ions you pull the exponent down with its sign so ph equals negative 1 times negative 3 or ph is going to equal positive 3. now you don't have to go through all this you can just say okay you take the exponent pull it down flip it and that's the ph so if you have 10 to the negative three the ph is positive three so that's how you can do ph but there's also poh and there's also ph comparison problems so the active office hours sheet is there and i'm going to post this lecture so that you can well this office hour so that you can see how it works did that help you somewhat yes thank you and we have another question okay and so if the if you have another class you're welcome to exit um i'm just gonna answer as many questions as i can and then the 10 30 class will be if you're in the 10 30 class we won't be starting that until 10 30. but yes go ahead could you explain the difference between polar non covalent bonds i understand the basics of it but not the charge that charges that go along with it okay sure so here's the water molecule so polar oh it's moving polar covalent and covalent is that what you said say that again saba polar and non-covalent polar okay so polar covalent is due to electronegativity electronegativity means that the atom one of the atoms is an electron hog oxygen and nitrogen in our class are going to be electron hogs they will not totally take the electrons and hold them but they have them a higher percentage of the time so if you were watching this for 100 seconds and it's unequal sharing for 90 seconds the electrons would be hogged by the oxygen and each hydrogen would get it for five seconds the hydrogens then become partially positive that's the partial sign it's like sideways like this and the partial negative charge forms on the electronegative element again in our class the two electronegative elements are nitrogen and oxygen if you see nitrogen with hydrogen or oxygen with hydrogen you're going to have polar covalent bonds these bonds in between the hydrogen and the oxygen are polar covalent it's unequal sharing and partial charges form regular nonpolar covalent are between like maybe two equal atoms so carbon and carbon they share equally like you get the electron and i get the electron then you get the electron then i get the electron so because there's equal sharing there's no partial charge that forms that's the difference between nonpolar covalent and polar covalent did that answer the question it must have they said yes thank you okay okay so we are about at the end of the session so if you're in the 9 30 class um you want to exit so that the 10 30 class can come back in um thank you for coming and again if you have any questions or problems we have the group me email and the office hours we have zarin her si and john the sarc sessions with lots of help in this class i have one last question um when the when do you put all the answers on the on the web course so i can check them as soon as i have another um active office hours until 11 30 and then i need to wait for this video to convert and i will be posting those answers probably by one o'clock i would say today or earlier okay and what about the practice problems okay five one five two guys those are up there the answers to those are up in the modules okay are there okay thank you question okay uh-huh when the elements are the same is it always going to be non-covalent most of the time for you guys yes thanks any other questions yeah question when you said non-covalent did you mean non-polar covalent or just not valid yeah non-polar covalent okay okay polar covalent and any other questions okay so if you're in 9 30 thank you for coming and if you're in 10 30 i know you're probably starting to come in now so we will start the next next session at about 10 30. i'm just going to mute my any last questions before i meet my mic and i need to stop the recording for this one and stuff okay