Intro to Chemistry & What is Chemistry? - [1-1-1]

hello welcome to chemistry my name is jason i'll be your teacher in this class and my goal in these sets of lessons in this entire journey that we're about to embark on is to take you from absolutely zero knowledge of anything about chemistry and really take you step by step through all of the sequence of topics needed so that you can be very not only proficient in chemistry but be confident and more important than that i really want to instill some excitement in you about learning this subject okay really i want to front load this class with the things that i really wished that people had taught me when i first learned chemistry because usually what you do is you jump into chemistry and start talking about atoms and molecules and reactions and before you know it you're you're a little bit lost in exactly what you're doing maybe and your problem solving skills are not maybe where they need to be and so you start struggling and then a lot of times you get discouraged but just like with anything that you learn in life whether it's learning how to talk or learning how to ride a bicycle or learning how to drive a car or whatever really none of us knows how to do these things in the beginning so what you need is someone to guide you by the hand and really show you by uh by by learning step by step that not only can you understand these things but you can really get a deep intuitive grasp of what it is you're trying to learn why call that uh i call that a mastery of something when you feel it in your bones and i really want you to feel chemistry in your bones i want you to wake up in the morning and say well that's a chemical process there how does that work and have some excitement and curiosity about that all right that's my goal i want to give you those tools so that you can be excited and kind of like ready to conquer this journey that's ahead of you now we do have to come back to reality a little bit why do students have problems in chemistry a lot of students have problems in chemistry i will tell you my opinion of what i see with the people that i teach the main reason they struggle is because of a couple of different reasons the main one is that every single chemistry problem almost every single problem is a word problem right so when you take algebra for instance i tell you solve an equation i just write the equation and bam you have some steps and you solve it and there's a certain way you're supposed to do it once you kind of get a feel for it you can just solve it right if you move on into trigonometry or calculus it's the same way in calculus i might say calculate this integral that's a topic you learn in calculus same kind of deal like boom boom boom you learn the techniques and the methods and you solve it right there's some word problems in there but most of those classes are based on just learning the steps and how to handle these different kinds of situations but in chemistry it's not like this it's it's never cookie cutter it's like you have 32.7 grams of sodium chloride in a vessel at 32 degrees celsius and then you increase the temperature of the vessel and you add some potassium whatever whatever to the thing what's going to happen how much chemical product will you form and also by the way will it form at all and if you increase the temperature by you know 50 celsius is it going to form differently there's so many different variations on problems that you really cannot just just read a problem and just know exactly what to do like you can in an algebra problem you can't and that's because they're all word problems now that's the bad news but the good news is it's conquerable and the way that you conquer it is you have to practice it there's really no way that you can do it without practicing you have to read a bunch of problems and you have to solve a bunch of problems and after a while you will know what's important in a problem and you will know how to set it up and you'll know how to put it together that is the crucial thing important thing number one about chemistry number two is that it all boils down to definitions you see if you don't know the definitions you can't follow anything right so if i tell you you have a molecular mass of this or if i tell you that you have a boiling point of this or i tell you that you have an isotopic abundance of blah blah blah well if you don't know what those things mean you can't do anything so in the beginning of the class we have to front load with some definitions and i i hate doing that because it kind of bogs us down a little bit but you have to trust me if we don't if we don't cut through these definitions of what atoms and molecules are for instance then later on you're just going to be lost and there's no reason for you to be lost because we can learn this i promise you i came from zero knowledge and we can all do it together and i promise that's my goal uh here to to help you with this all right why should we learn chemistry right why should we in my opinion chemistry is the most one of the most accessible sciences you know i love physics i have a degree in physics i've done a lot of physics in my life i really have a lot of passion for understanding advanced physics and i don't understand all of it of course nobody does but i have a deep appreciation for that and i enjoy that but the problem with physics is that once you get so far into it like you study the magnetic field of some you know situation or an electric field or you study electromagnetic waves right or you study whatever some entropy of something right the problem is that once you get back past the basic physics you kind of have a hard time visualizing what you're doing you start studying black holes or something at this in the center of a star like stellar fusion or something and it's hard to visualize what you're doing advanced physics is very hard to visualize because you can't see it and you can't touch it and you can't taste it and so it's hard for us to wrap our brain around but chemistry is very nice because once you understand the basics of what we're doing in chemistry then you can walk around your house and you can see chemistry everywhere literally everywhere you are interacting with something that someone has designed in a chemical way to benefit you and to serve some sort of purpose right for instance take something simple like a piece of plastic like this this pen here right it's made of plastic or think of a plastic baggie right that plastic baggie is very strong have you ever tried to take a bag a plastic bag and just rip it apart it's very very strong only if it's thin can you break it if you twist it up into like a twisty and then pull on it it's very hard to actually break it maybe you can't break it at all that's because the the atoms that are joined together to make plastic are what we call polymers and they are joined in very long chains that are very strong and those long chains that are strong make it very very very hard to break right it kind of behaves as a microscopic kind of rope inside there but also very flexible see plastic is very flexible but yet it's extremely strong if you try to break it and so we have a ton of uses for plastic something you may take for granted right other things you may look around the house you know even the aluminum foil the sheets of aluminum foil that you have that maybe you cook with right that was pressed into a certain shape and there's a certain chemical process to take the the ore out of the ground that is not pure aluminum by the way it's it's aluminum bonded to something else maybe bonded to oxygen or something and we have to remove the oxygen and get the pure aluminum out of it and make these pure sheets that we can then cook with right i can go on and on and on all the way from simple things like this to the tip of the matches if you take a match from your kitchen and strike it if you look at the end of the match there's there's the material that's on the end of that match it's got sulfur in it it's got some other stuff in it and it's designed so that if you give it a little bit of friction and a little bit of heat then that match burns that's a chemical process someone designed to fit on the tip of a match inexpensively so that we could use it to make fire quickly so plastic fire you know we talked about metals like aluminum also up to very advanced things like rocket engines right you take hydrogen which is the lightest most abundant element in the universe and you combine it with oxygen right so hydrogen is a gas oxygen is a gas you combine it together what happens you get a flame you get an explosion really and if you put that inside of a rocket engine then you generate thrust because of the heat you know that's produced in it all the water that is formed because hydrogen plus oxygen makes water h2o right and that flows out the back of the rocket and produces thrust you know i worked at nasa for many years so that's near and dear to my heart but you know chemical processes stretch all into even into space travel into everyday life around you so the thing i like about chemistry is that once you understand the basics of what you're doing you can actually see it in action all around you it's very hands-on and so that is one thing i really wanted to impress upon you now we have a ton of stuff to cover a ton of stuff to cover but real quick before we go any farther into definition just give you a couple more quick examples you may have seen baking soda in your pantry or in your your cabinet baking soda and vinegar and if you mix baking soda and vinegar you see the bubbling of the carbon dioxide gas right that is a chemical reaction that's going on just like if you take hydrogen and oxygen and put a flame to it you get water that is a chemical reaction where the two different kinds of atoms come together and make a new substance or a rearrangement in that case it was water but in the case of baking soda and vinegar you see the bubbling of the carbon dioxide gas you know we talked about the the matches in the sulfur and so on now the good news is that when you solve chemistry problems you know really the math doesn't go really beyond addition subtraction multiplication and division i mean sometimes you have more advanced equations of course when you get into advanced chemistry most of the time it's it's pretty simple arithmetic though so the math should never hold you back but what could hold you back is if you start trying to solve a problem without knowing what the problem's asking so in this class we're going to learn how to read a chemistry problem how to pull out the information that is required how to really understand what's being asked and then how to tackle the way in which we should get the solution in the correct way and also how to check our work and by doing that process over and over and over again you will get good at solving chemistry problems and i hope that it will also be enjoyable along the way all right so let's jump into the bulk of this this is just sort of the introduction now we need to really talk about chemistry a little bit more we talked about why studying chemistry let's talk about what is chemistry anyway my definition of what is chemistry now this is my definition of chemistry your definition may be slightly different if you have a textbook the definition and the textbook will be slightly different there's different ways to define chemistry my definition is chemistry is the study of the composition and the structure of matter and changes that occur in matter it's a short little definition but basically what we're trying to say here is that chemistry is studying the composition of matter and as we react things together in a chemical reaction how does that matter and the structure of matter change because we have the word changes here so i'll give you a good example we take sodium right which is a a a a metal on the periodic table we're going to talk about the periodic table in a minute it is a metal that is so reactive that if you drop it into a bowl of ice water it will catch on fire it will it will have a chemical reaction with the water and a lot of heat will be created and there will be a flame that is actually produced as part of that you don't want to be eating any pure sodium and then you have chlorine right chlorine is a uh kind of a yellowish looking gas that will kill you if you inhale it you die okay sodium and chlorine obviously are two totally different things that are not uh seemingly related to each other now we're going to talk about this in a minute why does sodium have the symbol in a we'll talk about that in a little bit sometimes the symbols don't exactly match up with the letters we use to represent them but if you take sodium and you combine it with chlorine these are two things that basically would kill you if you swallowed pure sodium you would have some sort of reaction in your stomach it wouldn't be pleasant i promise you chlorine will kill you but whenever you mix it together it forms something new bonded together called sodium chloride and sodium chloride is what you eat every day in table salt not only is table salt tasty but it's actually required for your body to function properly because when you eat the salt your body breaks down the sodium and the chlorine in the microscopic quantities that won't hurt you but those uh sodium and chlorine uh entities in your body they are used in the function of your nerves and your brain and you know all manner of uses inside of your body but the point i'm trying to get at here is sodium is something you don't want to eat chlorine is something you don't want to eat but together sodium chloride has a totally different character it is a crystal that is kind of shiny you've seen what salt looks like under a microscope right it's a little shiny little crystal but it's perfectly fine to eat in fact we need it to survive it's salt right so when you put things together the atoms are rearranged into some product that has a totally different set of characteristics compared to what goes into this guy right and this is what i called a chemical reaction as we recombine things in different ways we have new products that are formed which we then can use and that we that have different properties than what we started with all right what about i'm just going to write it in word words would burning right so what i mean by wood burning is there there are chemical uh chemical compounds we'll talk exactly what the word compound means in a minute inside of wood that contain long chains of carbon right lots of different ones and whenever you add oxygen to wood of course we have an atmosphere full of oxygen and you add heat to it we get the familiar uh the familiar idea of burning wood right and what do you get when you burn wood you get a new rearrangement of what you had started with you get co2 which is carbon dioxide gas but you also get h2o which is water almost everything that burns that has carbon in it is going to produce carbon dioxide and h2o water we're going to talk a lot in the future as to why these things are almost always produced but the point is is wood doesn't look anything like a carbon dioxide which is a gas wood doesn't look anything like water which as it's floating up from the campfire is a gas but when you combine it with the oxygen and you add a little bit of heat those atoms that are in the wood the carbon and the hydrogen and the other things that are in the wood they can be combined with the oxygen from the air and rearrange in a different structure than what we started with and that has totally different properties carbon dioxide is a is a colorless gas that floats away of course we breathe out carbon dioxide as well from the respiration of our own cells which produce carbon dioxide as a waste product as well much like wood burning and it also produces water which of course is totally different as well so these products are a rearrangement so we say chemistry is a study in the composition of structure of matter and changes that occur in matter the changes that occur are because the atoms rearrange themselves and form new products with different properties than what we started with all right another example would be iron rusting right if you take a a bar of iron throw it in the yard iron might be you know very shiny when you first get it if you polish it really good everything looks great and you throw it in the yard leave it there for a few weeks and go back then the iron bar will not look beautiful anymore it'll look a little brownish a little bit uh maybe not as lustrous as it used to be and if you start scraping at it that brown substance will kind of flake off that's iron oxide right that's the iron that has now been combined with oxygen to form something new iron oxide and that iron oxide is not strong and doesn't have the same properties as the pure iron it is different properties because it's now combined with oxygen so it's a rearrangement of the atoms right and then of course we have the famous the big one the the super important one we have hydrogen right and then we add to it oxygen right and of course we have add a little heat and what do we get we get h2o and this is rocket fuel hydrogen plus oxygen gives you water and you also uh have heat that comes out of there and the water is expelled out very forcefully and so you have an explosion that's basically going on as well all right so that is what chemistry is it's a rearrangement of these of these things that we haven't talked about yet but they are atoms and they are the most indivisible uh i shouldn't say indivisible they are the most elemental fundamental thing that everything around us is made up of and that brings us to our second definition what is an atom anyway it is the smallest elemental unit in a sample of matter that retains its identity and that sounds weird what does it mean to retain your identity what it is what i mean by that is a long time ago people you know people saw carbon dioxide they saw water they saw carbon monoxide they saw sodium chloride they saw all of the things that existed in nature and they all look like completely different substances right because water looks totally different than hydrogen and oxygen and so obviously they thought they were totally different things but after a lot of investigation we figured out that everything around you all of the very different things that we think are so different around us are really just a rearrangement of these little at the time they thought they were indivisible we'll talk about that in a minute but these small little indivisible things which we call atoms and now we know that there are about a hundred different types of atoms in reality there's about 118 that we have created because the the really heavy uh atoms are uh not really naturally occurring we have to create them in a laboratory and they don't last very long so at the very end of the periodic table the very heaviest atoms are things that are not uh really very stable they don't exist in nature maybe they're radioactive so you can count those if you want but they're not things that we're going to study in this class in the bulk of the periodic table it exists of about a hundred elements that are natural and stable and the point i'm trying to make here is that all of the things that look so different around us are really just different combinations of those roughly 100 different atoms of course there's a few more in reality that we've discovered but those are the ones that are common right nickel iron hydrogen oxygen chlorine i can go on and on lead those are the atoms which were also called elements on the periodic table those are the fundamental things that what do we say smallest elemental unit in a sample of matter that retains its identity what do we mean by that if i take a sample and start cutting it in half and cutting it in half and cutting it in half like a bar of pure aluminum let's say i cut it in half and cut it in half eventually i'm going to get down to a single aluminum atom and that atom we're going to learn a whole lot more about how atoms our modern theory of how atoms are constructed later but for now just know that if we try to take that atom of alumina and break it in half then we don't have anything that behaves like aluminum anymore so we have something smaller than an atom in that case so we say atoms are the smallest elemental unit in a sample of matter that retains its identity because if you get down to a single aluminum atom it has all the properties of aluminum it's shiny you know maybe it conducts heat maybe it doesn't or whatever the element is it has all of the properties of that substance but if you take a single atom and try to break it in half then it has no characteristics of aluminum anymore because you you're now digging inside of the atom now i'll clue you in because i know that you already know anyway and we're going to get into this a whole lot more later we now know that most of the mass of the atom is concentrated in the center of the atom called the nucleus and those are where what we call protons live and neutrons live we're going to talk about this a lot later on so does not get bogged down in it right now but that is what is in the center of the nucleus right and then we have the electrons which are kind of orbiting and we'll talk a little bit more about orbiting later but they're in a cloud that surrounds the nucleus and together those the the nucleus plus the electrons form the atom so if you try to split the atom in half then you don't have aluminum anymore you have something else because you now have kind of digging into the nucleus to the to the root of the protons and the neutrons that are in there and so those are called subatomic particles protons and neutrons and electrons because they're smaller than an atom now back in the day of early chemistry that we didn't know anything about electrons we didn't know protons existed or neutrons existed so the definition they came up with was atoms were the smallest indivisible things that retained its identity but now of course we know we can split atoms apart into protons and neutrons electrons and we even know now that we can actually even split the neutrons and the protons up into something even smaller than that and those are called quarks and i know that sounds weird but that's a fact we know that quarks are what make up the neutrons and the protons turns out electrons don't seem to be made of anything smaller that we know of they really are indivisible now all of this is our current understanding it could all change which leads me to my next point i want you as you learn chemistry as you read your book as you watch my lectures i want you to learn but i want you to also realize that we don't know so much about how this stuff works and i want you to really absorb that because it's very easy when you read a book to say well all this is figured out i'll just learn it there's nothing else to learn but actually when you dig a little deeper than the surface layer on anything you will realize that we don't know anything about how this stuff really works what i mean by that is a little silly of course we know some stuff but the details of how the electron behaves in the atom we don't really know exactly the details of exactly how things behave how the chemical bonds work how they break and how they form yes we have theories on how they somewhat work but we also have situations we don't totally understand how exactly do the bonds break and form exactly on a nanosecond by nanosecond basis those are areas of active research how do we make chemical compounds of a certain shape in a certain size to perform a certain function those are things people are researching so when you read this stuff and when you learn this stuff and when you watch me talk and talk and talk talk about it and it seems like we know everything in the back of your mind i want you to know there's tons we don't know and there's tons of room for you to make that next discovery that's what i want you to know because i want some people watching this to get excited and get pumped up and learn this stuff and take the tools and then go discover the next big thing all right so we've talked about what is chemistry we've talked about atoms right some examples of atoms right we've talked about a lot of these already we know we have oxygen right oxygen is on the periodic table and we're going to talk about the periodic table a little bit better but the period a little bit later the periodic table is a organizational chart that shows all of the atoms that we know about and uh it's ordered it goes in order of increasing what we call atomic number in the nucleus so the nucleus contains the protons and the neutrons and as we add protons in the nucleus we get a different element so hydrogen has one proton helium has two protons and you go up the periodic table as you add protons to the nucleus you get heavier and heavier elements that are totally different characteristics but that table is structured in such a way that makes doing chemistry easier and we'll talk a lot more about that later but we have oxygen the chemical symbol of that is just the letter o we have nitrogen chemical symbol for this just in so far it makes sense right o goes with o n goes within we have carbon very important c in fact i want to talk about carbon for a split second you know all life that we know about on this planet has carbon as a building block and we're going to learn a lot about that later the reason life is built on carbon is because carbon can bond to itself in ways that other elements can't it can basically form four bonds at once and that allows you to make very long complex chains of carbon and other elements can also bond in chains but not quite as good as carbon can there's other characteristics of carbon that make it where life is favors it but that's the big one that carbon can bond in ways other elements can't and it can make longer chains now the dna molecule in your body of course is a carbon chain with all other things on there as well it's not just carbon it's other stuff too but if carbon couldn't bond the way it could then we couldn't have long chains of atoms and you wouldn't have dna and then you wouldn't have life so carbon is extremely important in fact it's so important that after you finish chemistry one and chemistry two we have an entire class in fact two or three classes that's called organic chemistry that's only talking about the chemistry of carbon carbon atoms carbon molecules so we have an entire set of learning dedicated to learning about how carbon works because it's so important for everyday you know earth and for life uh as as we know it and so on right now i do want to talk about another one here iron now the chemical symbol for iron you would think would be f uh uh here but actually or you would think would be i sorry you would think it could be i i for iron but actually it's fe now some of these most of the elements on the periodic table we just picked the first letter or the first couple of letters to to represent them but sometimes the elements are totally different than the first letter and that's because when they first started doing this stuff they all worked in latin the scientists worked in latin so a lot of the the symbols in the periodic table come from the latin version of that material so for instance iron fe comes from the latin which is ferrous now i'm not going to ask you or tell you to memorize you know these latin roots i'm just letting you know sometimes some of these off the periodic table they look a little bit weird another one be sodium you think sodium would be s or so but actually sodium is in a and you have chlorine you think chlorine would be ch it's actually cl right so basically the elements on the periodic table are going to be represented by a symbol either a single letter or two letters and sometimes the two letters are correspond to the word and sometimes the two letters come from latin so you're just going to have to eventually through working with it you'll you'll remember the ones that are that don't exactly match the word that they come from all right so we talked about atom smallest elemental unit in a sample of matter that retains its identity because if you try to split the atom up then you're into the things inside you're breaking it apart into the protons and the neutrons and all protons look the same all neutrons look the same if you had a bucket of electrons if you could just put a bucket of electrons here it would all they would all look the same they don't have any difference in the character there only when they're combined in these ways these different elements have different characters all right now the next thing we're going to talk about is the concept of a molecule a molecule a molecule is a larger unit in which two or more atoms are joined which we call in chemistry bonded together so i know that you all have an idea of what a molecule is it's kind of an in everyday language you know this or that i know that you have an idea of it because we've all heard it before you take chemistry class but we have to make sure we are on the same definition and in our definition a molecule is when you take two or more atoms and you join them together into their own little unit where they float around together kind of hook together because these things do in some cases like to bond together like h2o water they are bonded together in a unit and that unit is called a molecule so it's a larger unit in which two or more atoms are joined which in chemistry we call bonded together all right so the most famous of this of course is h oops if i can write h right h2o right two atoms of hydrogen and one atom of oxygen other examples carbon monoxide carbon dioxide co2 so one atom of carbon two atoms of oxygen joined together as a unit which can free float around by itself which we call a molecule now molecules do not have to be different elements like this actually we can have sometimes the same molecule bonded to itself for example if you take two atoms of oxygen and bring them together they actually form a molecule called o2 oxygen gas right so you may have heard in the movies in the hospital they'll say turn on the o2 the patient needs o2 or sometimes if you watch nasa and rocket launches they'll say you know the o2 we're ready to go with the o2 for you know launching the rocket because the o2 is the is the is part of the rocket fuel it's actually what we call the oxidizer but in any case it's part of what goes into the engine to burn to make the rocket fuel it turns out that atoms of oxygen really don't like to stay separated they actually join up together and they form a molecule they bond together in pairs and that's why we have o2 so if you've ever heard of o2 gas that is what that means because they are not usually separated they're they're bonded together and we're going to learn exactly why oxygen likes to do that later not all atoms do it but some do this of course is a molecule you can also have nitrogen which also likes to bond with itself in two hydrogen likes to bond with itself so it actually forms a molecule of two hydrogen atoms which are clumped together bonded together chlorine is another example chlorine likes to bond to itself as well so these are all molecules right they're all molecules because the molecule is any time two atoms really come together and hook hook together like this and bond together the whole concept of bonding we need to have a whole lesson on because that's a whole bag of that's a whole bag of worms we've got to talk about there's a lot to understand about bonding we don't even totally understand exactly how bonding works right now if a chemist chemist tells you oh yeah i know how bonding works they're lying to you because really we have our theories it goes into quantum mechanics right quantum chemistry and we have equations that predict bonding but the actual details of exactly how it happens we don't understand all of those details especially for more complicated molecules than these that's why i'm saying there's always opportunities for someone else to make the next big discovery all right so we have molecules these are when multiple atoms join together uh and uh you know we can have the same atom bond to itself these are still molecules we can have different atoms come together and these are just very simple molecules but we can have molecules with five or ten different atoms we can actually even have molecules form a chain or even a ring we can actually form a circle you know i told you carbon can bond in very neat ways carbon can actually take and bond itself into a circle uh different size circles is small circles with five or six atoms and ten or twenty circles we're going to talk a lot about that later especially if you take an organic chemistry class so that is what a molecule is and i think i want to talk just as an aside for a second before i jump into the next part of this because after we talk about molecules i want to talk about chemical reactions right and chemical reactions are really what all of chemistry is actually about but before we get into this i want to impress upon you something that i really wish someone had told me when i learned chemistry because it's really the number one thing that's going to make chemistry understandable for you right as you get past the surface layer most people can understand atoms and molecules and but when you get into reactions you start trying to understand why they why they're happening and why they're not happening why should the reaction happen or maybe sometimes the reaction doesn't happen and you start to kind of wonder why sometimes it happens and sometimes it doesn't happen well let me tell you the punchline to this right now i can't give you all the answers but i can give you a big piece of the puzzle and i can give it to you right now in lesson number one all right here it is so you know that you have protons which are positive right and you have electrons which are negative and you know that opposites attract so by now you should have learned that protons and electrons attract each other and like signs repel so two electrons push apart and two protons also push apart all right i hope that i'm going to blow your mind in a second when i tell you that this a force of attraction between protons and electrons we call it the electrostatic force electro because related to electricity because of charges static because there's no current flowing but it's called electrostatic so they're just sitting there nothing's really happening but they're attracting each other right so that big word electrostatic don't let it scare you it just means electric force right the electric force that exists between two charged particles like two protons or two electro a proton an electron or or a repulsive force between two electrons that kind of thing the electric force is millions of times stronger than the gravitational force holding me to the ground right now i'm going to say that again because it isn't something that makes sense and you need to absorb it because it really does govern all of chemistry all of chemistry and i do mean it governs all of chemistry the electric force the force between an electron and a proton the attractive force that happens there right it's millions and millions and millions of times stronger than gravity it is way stronger than we think of in our everyday life and because it is so incredibly strong then that is what is driving pretty much everything in chemistry right when you mix two things together sometimes they don't react and sometimes in a different situation different set of things you mix together they do react to form something new but what governs what determines if the thing reacts or if it doesn't it's the electric force if the situation that you put those uh atoms in are in such a way that the electric force is strong enough then it's going to rearrange what's going on and it's going to come together and everything's going to stick together in a way to rearrange to form the products right because the electric force is what's governing all of the chemistry that's happening the electric or the chemical reaction that's happening right but if you mix two things together and nothing chemically occurs there's plenty of things you mix together and nothing will happen at all right well why doesn't anything happen well it's because everything was already stable and the electric forces that were present were just not strong enough to overcome that and rearrange the things into something new so nothing happens it literally boils down to that in a few chapters from now we're going to talk about properties of the periodic table we're going to talk about how readily does a element donate an electron or give up an electron or take an electron right um when does that happen how readily does that happen we're going to talk about the boiling point and the melting point of substances we're going to talk about how often or how much energy does it take to take an electron from one atom and move it over to another atom right all of that stuff comes from the strength of the electric force right the strength of the electric force governs everything it governs the the properties of the atoms on the periodic table how easily do they give an electron away how much do they want to take an electron from someone else all of that stuff is coming from how strong that electric force is so later on when we tell you the rules to try to figure out what's going to happen because all of this chemistry is happening because electrons are being shared or transferred between the two things you're mixing together and then things can be rearranged into a new set of products right but that transfer of electrons the sharing of electrons that might happen the rearrangement that might be happening to give you the product it's all predicated on that electric force being strong enough to make it happen and when it is strong enough to make it happen then it happens but if the situation was already so stable so that you know the electro forces there are are not going to make any changes then nothing happens and all of those properties that we learn about a little bit later in the periodic table they all come from understanding the strength of the electric forces because you've got to remember and i know we haven't gotten into it yet but i know that you all know that in the center of all of these uh in the center of all of these um atoms we have little protons right maybe you have more than one right then you have maybe a couple neutrons that really don't have any charge at all and then on the outside maybe there's a couple of electrons and we say that the electrons kind of go around and they kind of orbit now there's a whole lot more to this it doesn't really really look like that but that's the picture that we tell everyone to understand and so we know that the protons and the electrons are attracting each other and once you understand that the strength of that attraction is millions and millions of times stronger than gravity then you can understand how all of the chemistry that you learn in this class is dominated by what that force is going to do now you might say if it's so strong why don't i feel it every day i mean i don't feel any anybody pulling on me okay well the reason you don't feel it is because if you look at this atom and you zoom out you're gonna see two protons and you're seeing two electrons so from a million miles away then you're gonna see an equal and opposite amount of charge and when you have an equal and opposite amount of charge what happens if you add just think from algebra plus two and this is negative two because these are negative what do you have when you have plus two and and you add two at a negative two you get zero so anytime you have an equal and opposite amount of charges then from a distance far away it looks completely neutral it looks like zero charge because everything cancels out but you see in chemistry things don't cancel out because in chemistry if you bring two things together one electron may get shared between the molecules or maybe jump from one atom to another then you have a charge imbalance then things start moving around and try to attract and rearrange themselves into a more stable configuration that's what's called a chemical reaction but that chemical reaction is driven by the electrons that are moving and the forces that come about when electrons start becoming unbalanced and start moving around like that and i know i went on and on and on about it but i i just i gotta tell you this early on because i could go six chapters in and then explain it to you but then it's like man that would be a wasted opportunity for you to understand that this electric force is millions of times stronger than gravity i'll leave you with one final thing before we move on i'm standing here in front of this camera but with the but the energy in my muscles right just standing here i can jump off the ground just with the energy in my little tiny puny body i can lift myself and remove myself from this planet but consider that every atom on this planet is attracting my body with gravity the himalayas which are on the other side of the planet they're attracting my body because of gravity right the center of the earth thousands of miles away is attracting my body someone on the other side of the planet in their car they're attracting every atom on this planet is pulling down on me but yet i am strong enough to push up and separate myself from all of that attraction with my little bitty muscle energy that tells you that even though we kind of think as gravity as being strong gravity is actually really weak right it's really not that strong at all and when you do the math which i'll do for you one day you will find out that the equation that governs gravity which i could write on the board but i don't want to do it too early because we've got to save some stuff for later right it looks almost exactly the same as the equation that tells you how two electrons repel or how an electron and a proton attract each other the equations look the same they have the same force they have the same form i mean however the electric force is millions and millions and millions of times stronger right in fact just to give you an idea of how much stronger it is if you remember back from math right if you remember back from math um if you have 10 squared that's 10 times 10 which is 100 right 10 squared means 10 times 10's 100. if you have 10 to the third power that's 10 times 10 times 10 that's a thousand right if you have 10 to the sixth power that's 1 million right so you see what's going on because the number that you have in the exponent that's how many zeros you have here so there's six zeros here because of this but the electric force is actually 10 to the 39th power stronger than gravity that is a 1 with 39 zeros at the end think about it a million as only six zeros after the one but the electric force is a one followed by 39 zeros that's many many many many many millions of times stronger the only reason we don't see it is because we have equal numbers of electrons and protons so they cancel each other out but in chemistry they don't cancel each other out because when one electron moves from one atom to the other you have a charge imbalance and that causes everything to move to find its more stable positioning which leads to what we call when we study this stuff chemistry that is why chemistry is happening that is the stuff that you could spend the rest of your life studying if you really wanted to understand it in great detail all right so chemical reaction let's move on to chemical reaction and then we're gonna we're gonna wrap it up here chemical reaction is when matter undergoes a change in arrangement and or structure of its molecules and now you know all of these chemical reactions are really happening because the electric force is so strong that if there's ever any imbalance anywhere things are going to rearrange to get to the lowest uh more stable configuration of a state that's what we call chemistry and of course the big one hydrogen right plus oxygen gives you water h2o i could write carbon plus oxygen gives you either carbon monoxide or carbon dioxide why does it form carbon monoxide with one atom of each sometimes and why does it form carbon dioxide with two atoms of oxygen sometimes well we're going to talk about that it does different things in different situations but when you combine these things together the electrons are transferred or shared in such a way that whatever we form on the end here is a more stable configuration than what we started with we're going to talk a whole lot more about what that means in a little bit all right moving right along we talked about molecules we talked about chemical reactions let's move back over here to the beginning i promise we're almost done here let's talk about elements now i know that you've heard the periodic table of the elements you've heard me use the word elements for our definitions we're going to say it's the same as an atom if you hear the word atom if you hear the word element they mean the same thing from our point of view i'm not saying there could be some other situation down the road where you might have something going on different but for us if i say here is an element of the periodic table in your mind you want to say well that's just a different kind of atom that's a unique atom that we have listed on this thing called the periodic table common elements you already know we have oxygen you know we have nitrogen we have sodium right which goes into table salt sodium chloride we have argon you know and we also have things like neon you might see those neon signs you know that glow orange or whatever right so we have all of these different symbols on the periodic table we call it the periodic table of the elements you could also call it the periodic table of atoms because elements and atoms are the same thing okay moving right along we have discussed this before but we're going to tie our you know dot our eyes and cross our t's right here we have the idea of a compound right a compound is basically a molecule with two or more different elements you might say wait a minute how's that different than a molecule let's go back to the definition of a molecule that's why i wrote everything down a molecule is a larger unit in which two or more atoms are joined bonded together and we gave lots of examples so a molecule is anytime a molecule is like the general class of what's going on a molecule is any time you have two or more things coming together and what we call bonding almost everything in chemistry we study is some sort of molecule not always but but very very often right let's give a couple of examples all right let's talk about co2 this is carbon dioxide one atom of carbon two atoms of oxygen bonded together now this is a molecule it a molecule because it's it's two or more things that are stuck together anytime that happens it's always called a molecule but this is also called a compound why because these two elements that came together were different when they're different we call them we call it a compound that comes together right what about the famous h2o right this is a molecule i'm going to put little quotation marks it's a molecule it's also a compound because it's a molecule because it comes together two or more different things uh and because they're different elements that come together it's called a compound what about the famous h2o2 you know what that is h2o2 is hydrogen peroxide you use that to clean cuts right it is a molecule because it is any time two or more things come together notice we have four atoms here two atoms of hydrogen and two atoms of oxygen so it's four atoms here but it's also a compound because it's different elements so you might say well wait a minute everything you've listed here is a molecule and a compound so when can it be different let's talk about the oxygen molecule you just call it o2 right well this is a molecule because it's two or more things stuck together but it's not a compound it's not a compound right the reason it's not a compound is because it's the same element stuck together it's only a compound when it's two or more differently named different items that come together then it's called a compound these are different and they're stuck together so it's a molecule and a compound these are different they're stuck together so it's a molecule and a compound these are different so it's a molecule and a compound these are the same atoms so it is a molecule but it's not a compound right what about nitrogen gas right same thing it's a molecule and not a compound what about chlorine gas well it's a molecule but it's also not a compound so i just want you to remember most of the time things that we study are compounds because most of the time the things you're studying are not the simple ones like oxygen gas or nitrogen gas o2 into cl2 h2 hydrogen gas usually we're studying other things like methane or something like that with lots of different elements in there so we almost always call them compounds but just so you know it's only really a compound if the things that are made up of that molecule are different items all right and we're going to round out the tail end of this lesson by talking about mixtures now so far we've talked about chemical reactions we talked about things coming together rearranging their electrons rearranging their atoms and coming out with a new arrangement which we call the products of the the outcome of the reaction so that's chemistry right but we also have this other thing that we want to compare it with which we call a mixture in a mixture there's no chemistry happening at all it's just taking two objects and literally mixing them together but nothing chemically is happening so i'm not even going to write down the definition of this because i think it's easy enough to understand it's basically when you have two or more items or or samples of of things mixed together that uh where no chemical reaction is happening so examples of this of mixtures you know well before i give you examples let me give you examples of the different kinds of mixtures and then we'll give specific examples right we have two different kinds of mixtures the first one is a homogeneous mixture homogeneous mixture right homogeneous homo means same homogeneous mixture means that the mixture that you have has the same composition everywhere same composition everywhere right so examples of this right would be something like salt dissolved in water you know in water the salt is dissolved and uh the the the salt is it doesn't disappear it's just in between all of the water molecules that are there and whether or not you take a drink of water the salt water from the top or if you take a drink of the salt water from the bottom it's going to taste the same saltiness because once everything is evenly distributed and dissolved then we have the same concentration of salt everywhere so that's called a homogeneous mixture all of these solutions like sugar and water salt and water other things dissolved in water they're going to be homogeneous situations if you take sand with rocks and pebbles and you mix it up really really really good and you have a very uniform situation no clumping that's what we call a homogeneous mixture but we also have the situation where it's not homogeneous we have heterogeneous mixture we have the heterogeneous mixture so homo means same hetero means different so different uh different composition in the mixture so what we see here when we have a heterogeneous mixture is the uh it varies in composition so here i'm going to put as an example i'm going to put beach sand now you could mix the sand really really well but if you don't really mix it if you take one scoop of sand from one part of the beach and then go five miles away down the beach and take another sample of sand then the compositions are going to be a little bit different right because the sand on the beach has not been mixed thoroughly it's just deposited by the ocean so it's going to be a little different you're still going to have similar things going on but it's not evenly mixed or evenly distributed so we call it a heterogeneous mixture another example would be like rocks and dirt now if i mix the rocks and dirt really really really well if i pulverize the rocks to get it really uniformly distributed with the dirt you could say it's it's homogeneous but if you just throw some rocks in the dirt and do a little shaking it's not going to be uniformly distributed we call that a heterogeneous mixture so we have mixtures which nothing chemically is happening we just have two or more species coming together and mixing when you have these mixtures where everything is very evenly mixed very uniform we call it homogeneous mixture any kind of solution where things are dissolved or homogeneous and then you have the heterogeneous mixtures where things are just clumpy and not mixed very well at all now i want to wrap up this lesson with a conclusion um and i do want to wrap this up with a conclusion and i'm going to do that now but i'm going to give you a little bonus material at the end before i do that because it's on my mind and i don't want to forget to mention it i'm sure i'll mention it and we'll have entire lessons in the future but while it's on my mind i do want to tell you a few things and i'm going to close by kind of giving you a road map as to what you really learned throughout chemistry from here on out to the next lesson all the way to the end of the road kind of deal before we do that i want to go back to what we talked a minute ago i talked about the electric force is millions and millions of times stronger than gravity i keep harping on that because it really governs everything it governs how the atoms how they start to share when they gain and lose electrons and that leads to all the chemistry that we have all of the chemistry that we have is all due to electrons moving around on the outer layers of the of the of the shells of the atom of the atoms that are mixed together sometimes they share electrons and sometimes they transfer electrons and all of that sharing and transferring comes from the strength of the coulomb forward that's called the coulomb force also called the electric force and because of that because all of the chemistry that we have is due to that then all of the chemical bonding is also due to the strength of the electric force right so we're going to learn about single bonds and we're going to learn about double bonds and we're going to learn about triple bonds and they're different strength of bonds right some bonds some chemical bonds are stronger than others and the strength of the bond it comes directly from how strong from how strong that co that electric force is right right and then i'm going to talk about the most important molecule in our world which is called h2o now the way we write h2o is two atoms of hydrogen and one atom of oxygen now later on we're going to get into this a lot more we're gonna have entire chapters on this later but the way this thing is written is or the way this thing if you could zoom in on a microscope and see one atom you wouldn't see a little letter here h2 and oh you wouldn't see that you would see something like this you would see the oxygen atom in the center and these two hydrogens would be off to the side but it wouldn't be in a line it turns out that the water molecules actually bent a little bit and i'll explain why in just a minute but here are the two atoms of hydrogen and the single atom of oxygen and this line that joins from here to here and this line that joins from here to here shows the idea that the oxygen is bonded to the hydrogen and when we say bonded generally it means we're sharing electrons so there's other situations we'll talk about it later but usually we're sharing electrons you might say why are they sharing electrons well you can't get too far ahead of me here okay we got to go crawl before we walk the reason they share electrons is all because of that electric force is so strong that is why if you really get down to it that's why and also there's a lot of quantum mechanics which is way beyond the scope of this lesson that gets into why atoms bond with each other but i just for now we have to crawl before we walk and these lines are representing a single bond from here to from here to this hydrogen from the here to this oxygen now why is it bent we're going to talk about why it's been we're going to have an entire chapter trying to understand what molecules look like when we actually draw them out if we could zoom in and look at them and some of them have weird shapes and water is a bent molecule right the other thing that i want to impress upon you is that not all atoms attract the electrons with the same strength it turns out that oxygen is an electron hog it loves to attract electrons and when i say it loves i don't mean that it has a personality i mean that the electric force is stronger on the oxygen to pull it to pull the electrons closer to it so because of that see this line represents a sharing of the electrons between the hydrogen and the oxygen in a sharing here between the oxygen and the hydrogen but since oxygen is so much stronger at pulling at pulling the electrons that are here they're actually not in the the shared electrons are not like in the middle they're pulled a little bit closer to the oxygen these shared electrons here they're not in the middle they're pulled a little bit closer to the oxygen so because of that the oxygen has a little bit of a slight negative charge and this little symbol is a greek letter delta it's a it's a delta and i don't care so much about what symbol you use i just want you to focus on there's a minus sign here and because the electrons are pulled this way and pulled this way the oxygen which normally would have a zero charge it's pulling the electrons a little bit closer towards it why because of electric force if you ever ask why in chemistry it's almost always because of the electric force is so strong okay and because it's unbalanced and it's unequal in the shearing then there's a teeny tiny tiny more negative charge around this oxygen and because of that there's a teeny tiny a bit a positive charge around this hydrogen and a teeny tiny about a bit of a positive charge around that hydrogen because you remember when these come together the hydrogen has its own electrons this hydrogen has its own electron these oxygen has its own electrons when they come together they share you would think they would share right in the middle so they're equally shared between the two however oxygen pulls the electrons a little closer and it pulls these electrons a little closer so if you zoom out and look at it it appears that the oxygen has a slightly more negative charge than these hydrogens which have a slightly more positive charge so don't worry about the greek symbol focus on that the hydrogens are very slightly positive and the oxygens are very slightly negative so normally we don't talk about this for about five chapters in the chemistry or six or seven chapters this idea that the oxygen is a little more negative and the hydrogen is a little more positive this is called polar this means water is polar polar um just means that one side of the molecule is a slightly uh negative charge and the other side of the molecule is a slightly positive charge now why did i tell you this because this is just an introduction i don't have to tell you this now we're going to have an entire chapter talking about this right why well it's incredibly important that water is polar i'm trying to give you motivation more than anything i'm trying to get you excited i'm trying to get you to be like wow that's neat i didn't know that well all the water you drink is very slightly negative on the oxygen and very slightly positive on the hydrogen now why do we care about that well because if i put salt in the water the salt is also bonded together and it falls into the water but you see since part of the water is negative and part of the water is positive this negative side is going to attract the sodium out of the salt and the uh the details don't matter but one side of the oxygen is going to attract one side of the salt and the other side of the hydrogen side of the water is going to attract the other side of the salt the sodium chloride and it's going to pull the sodium chloride apart what do you think that means when sodium chloride gets pulled apart it means it dissolves so when you pour salt in a glass i want you to start thinking microscopically what's happened it's trillions and trillions and trillions of water molecules which one half of which are positive and the other half is negative and all together it allows you because the electric force is so strong this tiny little charge imbalance on the oxygen this slightly negative can attract the positive part of this of the sodium chloride salt and this tiny little positive charge on the hydrogen can attract the very slightly negative side of the salt and because they're pulling on different ends of the salt they pull the salt apart and they dissolve it if you put sugar in it dissolves the sugar and water turns out to be able to dissolve a lot of different things why am i bringing this up because your body is mostly water all the chemistry in your body relies on water why because all of the things that are happening that are important are dissolved in water your cells all the cells of your body they're basically chemistry little bags of chemistry happening inside of water and if water did not dissolve things then you wouldn't be able to have liquid chemistry inside of your body nothing would work because when you have things floating around in a liquid they can bump into each other and they can have chemistry with each other when you have salt poured into water and it dissolves the salt you have the salt broken apart literally broken up into a sodium and a chlorine sodium and a chlorine we'll talk about ions later but it pulls them into ions which are just basically breaking them in half but they're they're charged now and they're floating around in the water but in your body that means everything can be floating around and it allows chemistry to happen because when things are floating around they can bump in to other species and they can have chemical reactions so if the electric force wasn't that strong then water would not be a polar molecule which means it wouldn't have a positive and a negative side and if that didn't happen then water wouldn't dissolve anything and if that didn't happen you wouldn't have chemistry for your body and it also means ice wouldn't float because ice also floats because of this charge imbalance and i'll talk about that later but it has to do with when you cool down water it it has to do with these charges on the hydrogens and the oxygens they are what causes ice to form the structure that ice forms it causes them to join up in a certain way to form the structure of the ice crystal and that joining is what causes ice to float and if ice didn't float then long time ago all of the oceans would have just froze over from the bottom up and there'd be no fishes and no you know no no life on earth so i guess i'm just trying to give you a little bit of motivation that something as simple as oh i tell you the electric force is so incredibly strong believe me it's strong and you're like okay i get it but now i'm trying to give you a practical thing if it wasn't that strong then water would not have this charge in balance it wouldn't be polar and if it wasn't polar nothing would dissolve and ice wouldn't float and that means we wouldn't have any life in the oceans because ice would be frozen solid because ice floats it means when ice floats to the top you could still have fish swimming on the bottom but if the oceans fl froze from the bottom then the whole thing just gets frozen solid right and you would never have any complex chemistry happening in a liquid vessel which is what your body is doing all the time so you wouldn't have any respiration you couldn't have any metabolism and you wouldn't have any life so everything literally comes back to how strong that electric force is it's millions of times stronger than gravity all right i've done enough talking i want to wrap this up the last part of what i'm going to leave you with is a road map for what we're going to study in the future we're going to study chemical compounds in detail we're going to talk about when they combine how they combine and how do we name them what do we call them and how to determine what happens when we have two things coming together then we're going to talk about chemical reactions when does a chemical reaction happen why does it happen and what forms on the other end of a chemical reaction and then we're going to calculate okay if i mix so many grams of reactants together that's the things you mix in the test tube how much grams of product am i going to get will it be solid liquid or gas that comes out the other end and how many grams of it will i have right and then we're going to talk about how much heat comes out of that chemical reaction or sometimes chemical reactions require heat to get started like when you burn the log nothing happens until you add heat some reactions don't happen unless you add heat to get it started some reactions are very they they liberate a lot of heat like rocket engines for instance they liberate a lot of heat so how much heat comes out of chemical reaction what is heat by the way it's a microscopic motion of atoms so we're going to talk a lot about what heat is and temperature is light released we're going to talk about what causes light to come out of a fire it's the electrons jumping around inside of the atom and they generate a photon of energy which we call light that comes out of that so a campfire is heat and light it's a chemical reaction also with electrons moving so we can see the light that comes out then we're going to talk a lot about the structure of molecules so you can write these things down like h2o and you know ch4 and other things you could just write them down with letters and and numbers but it doesn't tell you the structure it doesn't tell you the shape why is water bent like this it's not a straight line that doesn't make sense well it actually does make sense but we have to dive into the details of what's happening so we have to talk about electric structure we have to talk about electronic structure around every one of these atoms how are the electrons organized around the atom and how do they interplay when two things come together so we have to talk a lot about atoms and a lot about a little bit of quantum mechanics to understand how the electrons are structured around atoms and how they come together we're going to talk about the chemical bonds next single bond double bond triple bond and then all other flavors of bond called sigma bonds and pi bonds how are the electrons coming together to make a bond and what is a bond and why do bonds happen anyway because believe me that question is not as easy to answer as you might think we're still studying exactly how bonds happen right then we're going to talk about reaction rates how fast does a reaction happen how far will it go how much heat is released and how fast will it happen uh and then we're going to talk about gas laws solid liquid and then we have the gas phase where we're going to have you know what happens when you compress a gas what happens when a gas expands what kind of chemistry can you have with gases if any right and then we're going to talk quite a bit about solutions and intermolecular forces between the atoms and solutions and then at the very end we're going to talk a lot about quantum chemistry in that in fact you can go beyond this chemistry class to study an entire career in quantum chemistry and that's all about what is happening around that atom why do the electrons behave the way they do what is an electron anyway and let me clue you in an electron is not what i drew on the board you see a teacher told me a long time ago my favorite teacher i've ever had in my life in university he told me education was a series of lies and it took me a while to understand what he meant but what he meant is that i have to lie to you a little bit in the beginning so that you can understand something and then as you understand more and more i can i can tell you more truths so that you can make your own you know jump and make your net your own discoveries so at first we tell you that atoms look like this positive negative electrons they go round and round but actually this picture is not right so we have to talk about what do we really know about electrons and i'll give you a hint electrons are little bitty waves protons are also little bitty waves and even the light that you see are little bitty waves so it turns out that i can summarize about 50 years of quantum research in the early 20th century by telling you that we pretty much figured it figured out that everything is made of waves even the things that seem hard they're really made of microscopic little waves but we have to to treat this education as a series of lies we have to start somewhere and then we have to build step by step by step so that you gain confidence as you go and then we can get to the stuff down the line in which case we run out of road we have no more road and you then have the tools to continue and build your own road and make your own discoveries and that's the whole point of all this stuff that's all i want out of this is for you to learn and for you to move on and make your own discoveries i hope that you've learned something from this introductory lesson i tried to give you a road map i tried to give you definitions i tried to tell you some of the most profound things that i know about chemistry that can be explained in a few minutes that everything we said here is really just the surface we need to now go one level down below the surface so watch this a few times if you need follow me on to the next lesson we're going to continue our journey understanding chemistry

Channel: Math and Science

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Keywords: intro to chemistry, introduction to chemistry, chemistry class, chemistry tutor, what is chemistry, chemistry tutorial, periodic table, general chemistry, college chemistry, high school chemistry, chemistry basics, chemical properties, chemical reaction, polar water molecule, electron configuration, gas laws, ideal gas law, significant figures, significant figures chemistry, chemistry review, periodic table of the elements, element, atom, molecule, chemistry, organic chemistry

Id: pdyDmXtye2w

Length: 68min 39sec (4119 seconds)

Published: Tue May 03 2022