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Mass percent example.txt | Mass percentage is simply another way of finding the concentration of the solution. Mass percentage is equal to mass of some compound x divided by the total mass of the solution times 100. The 100 gives you the percentage. This is a fraction, so you divide mass by mass, so the units cancel out. So mass percent is unitless. Now let's do a problem with mass percentage. |
Mass percent example.txt | This is a fraction, so you divide mass by mass, so the units cancel out. So mass percent is unitless. Now let's do a problem with mass percentage. The question tells us that we have 49 grams of gold, 25 grams of carbon, .5 water. We need to find the mass percent of carbon, water and gold in our solution. The first step is to find the mass percentage of gold. |
Mass percent example.txt | The question tells us that we have 49 grams of gold, 25 grams of carbon, .5 water. We need to find the mass percent of carbon, water and gold in our solution. The first step is to find the mass percentage of gold. To find the mass percentage of gold, we simply use the formula. So 49 grams of gold divided by the total mass of the solution, 49 grams plus 25 grams plus now we can't add kilograms to grams. So the first step is to convert this to grams. |
Mass percent example.txt | To find the mass percentage of gold, we simply use the formula. So 49 grams of gold divided by the total mass of the solution, 49 grams plus 25 grams plus now we can't add kilograms to grams. So the first step is to convert this to grams. We get plus 500 grams. Now we multiply the whole thing by 100 to find the percentage, and we get 8.5%. The mass perceptive of gold is 8.5. |
Mass percent example.txt | We get plus 500 grams. Now we multiply the whole thing by 100 to find the percentage, and we get 8.5%. The mass perceptive of gold is 8.5. To find the mass perceptive carbon, we follow the same exact formula. 25 grams of carbon divided by the total grams of the solution multiplied by 100 gives us 4.4%. So the max percent of carbon is 4.4. |
Mass percent example.txt | To find the mass perceptive carbon, we follow the same exact formula. 25 grams of carbon divided by the total grams of the solution multiplied by 100 gives us 4.4%. So the max percent of carbon is 4.4. The last step could be done in two ways. One way, you simply use the formula. You plug things in, you find the result. |
Mass percent example.txt | The last step could be done in two ways. One way, you simply use the formula. You plug things in, you find the result. A quicker way would be simply to realize that if you add these guys up and subtracted from 100, we get the mass percent of the final thing final compound within our solution. Namely water. So 100 -8.5 plus 4.5 gives you 87. |
Second Law of Thermodynamics .txt | From the side ramp here of the heat engine, we can see that that's the case. The energy that comes from the hot body, some of that energy goes into doing work, expanding the piston increase, increasing the volume. And some of that goes into the cold body, decreasing the temperature as the piston moves back into its original position, thereby keeping the temperature constant. Okay, we know by conservation of energy that the input energy equals the output energy. That means QH, which means the energy input is equal to QC, the energy transferred into the cold body plus the work done by the system or by the molecules within the system. And this directly correlates the first law of thermodynamics. |
Second Law of Thermodynamics .txt | Okay, we know by conservation of energy that the input energy equals the output energy. That means QH, which means the energy input is equal to QC, the energy transferred into the cold body plus the work done by the system or by the molecules within the system. And this directly correlates the first law of thermodynamics. And in fact, it's the same thing. It's basically this. Okay, so we basically are saying that engines, heat engines aren't completely 100% efficient in converting heat into work. |
Second Law of Thermodynamics .txt | And in fact, it's the same thing. It's basically this. Okay, so we basically are saying that engines, heat engines aren't completely 100% efficient in converting heat into work. So how efficient are they? Well, this formula here where E stands for efficiency or engine efficiency, can basically tell you how efficient an engine is. If you know the temperature of the cold body and the temperature of the hot body, you can find the efficiency. |
Second Law of Thermodynamics .txt | So how efficient are they? Well, this formula here where E stands for efficiency or engine efficiency, can basically tell you how efficient an engine is. If you know the temperature of the cold body and the temperature of the hot body, you can find the efficiency. And this also shows you can see from algebra and basic calculus that ends, this becomes zero or tenths of zero. That is, as TC decreases and Th increases or the difference between these two guys increases, the efficiency also increases. Okay? |
Second Law of Thermodynamics .txt | And this also shows you can see from algebra and basic calculus that ends, this becomes zero or tenths of zero. That is, as TC decreases and Th increases or the difference between these two guys increases, the efficiency also increases. Okay? You can pluck some values in and you'll see that as this becomes smaller and this becomes larger, that E becomes more efficient. Okay, finally, let's talk about refrigerators and air conditioners. So refrigerators and air conditioners are basically reverse heat engines. |
Second Law of Thermodynamics .txt | You can pluck some values in and you'll see that as this becomes smaller and this becomes larger, that E becomes more efficient. Okay, finally, let's talk about refrigerators and air conditioners. So refrigerators and air conditioners are basically reverse heat engines. What actually happens is work is inputted so that heat can be transferred from a cold body to a hot body or energy can be transferred from a cold body to a hot body. This decreases the temperature of the system but increases the temperature of the outside. For example, in this room in the summer, if I have an air conditioner and I plug it into the outlet, the energy that goes into the air conditioner basically does work on the inside room. |
Homo-Lumo interactions.txt | In this lecture, I'd like to examine the homoluma interaction between compounds. So let's look at the following example. Let's suppose we have compound one and alkane reacting with compound two, our hydrochloric acid. So this is a simple additional reaction. So in this reaction, this alkin actively lowers based base. This acts as a lewis acid. |
Homo-Lumo interactions.txt | So this is a simple additional reaction. So in this reaction, this alkin actively lowers based base. This acts as a lewis acid. So this donates a pair of electrons. This accepts a pair of electrons. So our intermediate reactants are the intermediate carbocation that has a positive charge on this carbon and has an extra h that it got from the hydrochloric acid. |
Homo-Lumo interactions.txt | So this donates a pair of electrons. This accepts a pair of electrons. So our intermediate reactants are the intermediate carbocation that has a positive charge on this carbon and has an extra h that it got from the hydrochloric acid. Now, this chlorine, or chloride atom now has an extra pair of non bonding electrons, and so it develops a negative charge. In the second step of this addiction reaction, we have the chloride ion donating a pair of non bombing electrons. So this is our lewis base and our lewis acid. |
Homo-Lumo interactions.txt | Now, this chlorine, or chloride atom now has an extra pair of non bonding electrons, and so it develops a negative charge. In the second step of this addiction reaction, we have the chloride ion donating a pair of non bombing electrons. So this is our lewis base and our lewis acid. And so we form the following final product. So, let's examine this picture more closely using molecular and atomic orbitals. So let's draw our molecular orbitals or atomic orbitals for this reaction. |
Homo-Lumo interactions.txt | And so we form the following final product. So, let's examine this picture more closely using molecular and atomic orbitals. So let's draw our molecular orbitals or atomic orbitals for this reaction. So, here's our alkane. So our sigma bond and our pi bond, creating the double bond. What happens is this pair of electrons. |
Homo-Lumo interactions.txt | So, here's our alkane. So our sigma bond and our pi bond, creating the double bond. What happens is this pair of electrons. So, this bond is composed of a pair of electrons, one electron in this two p orbital and the second electron in this two p orbital. So these two electrons attack this h atom, taking that h atom away from this chlorine atom. And we develop the following diagram. |
Homo-Lumo interactions.txt | So, this bond is composed of a pair of electrons, one electron in this two p orbital and the second electron in this two p orbital. So these two electrons attack this h atom, taking that h atom away from this chlorine atom. And we develop the following diagram. So, this is our intermediate cargo cation. So, this bond has been formed, this cobalt sigma ch bond. And now we have a positive charge on this twopie orbital because we have 1233 electrons. |
Homo-Lumo interactions.txt | So, this is our intermediate cargo cation. So, this bond has been formed, this cobalt sigma ch bond. And now we have a positive charge on this twopie orbital because we have 1233 electrons. And that means we have a positive charge on the two p orbital. So, once again, this is SP two hybridized, and this is a planar molecule. So what happens next? |
Homo-Lumo interactions.txt | And that means we have a positive charge on the two p orbital. So, once again, this is SP two hybridized, and this is a planar molecule. So what happens next? Well, next we have this lewis base. We have our chloride atom. And this non bonding pair of electrons attacks or attaches overlaps with this two p orbital, forming our spinal product. |
Homo-Lumo interactions.txt | Well, next we have this lewis base. We have our chloride atom. And this non bonding pair of electrons attacks or attaches overlaps with this two p orbital, forming our spinal product. So, in the first step, this pi bond acted as a lewis base, donating this pair of electrons and this h atom on this compound on the hydrochloric acid active as a lewis acid, donating that h, donating that empty one s orbital. And likewise, here, this is the lewis acid because it has an empty two p orbital. And this is the lewis base because it has a pair of non bonding electrons. |
Homo-Lumo interactions.txt | So, in the first step, this pi bond acted as a lewis base, donating this pair of electrons and this h atom on this compound on the hydrochloric acid active as a lewis acid, donating that h, donating that empty one s orbital. And likewise, here, this is the lewis acid because it has an empty two p orbital. And this is the lewis base because it has a pair of non bonding electrons. So, what exactly is a lewis athens based reaction? So, a lewis athens based reaction is the interaction between a filled molecular orbital, as we saw here, and an antimolecular orbital. And this is known as a homolumo interaction. |
Homo-Lumo interactions.txt | So, what exactly is a lewis athens based reaction? So, a lewis athens based reaction is the interaction between a filled molecular orbital, as we saw here, and an antimolecular orbital. And this is known as a homolumo interaction. Homo simply meaning highest occupied molecular orbital, and lumo, meaning lowest unoccupied molecular orbital. So if we go back to the first step in this additional reaction, we see that our homo, the highest occupied molecular orbital, is the pi bond. So this is our lowest base. |
Homo-Lumo interactions.txt | Homo simply meaning highest occupied molecular orbital, and lumo, meaning lowest unoccupied molecular orbital. So if we go back to the first step in this additional reaction, we see that our homo, the highest occupied molecular orbital, is the pi bond. So this is our lowest base. And in this case, our lowest unoccupied molecular orbital is the antibonding Sigma Bond. Remember, the bonding Sigma Bond is completely filled. The antibonding has no electrons, and so that means it must be the lowest unoccupied molecular orbital. |
Homo-Lumo interactions.txt | And in this case, our lowest unoccupied molecular orbital is the antibonding Sigma Bond. Remember, the bonding Sigma Bond is completely filled. The antibonding has no electrons, and so that means it must be the lowest unoccupied molecular orbital. Likewise, in this step, this was our lumo lowest unoccupied molecular orbital. And this was our homo, the Lewis base. So let's look at the second more closely in terms of energy. |
Homo-Lumo interactions.txt | Likewise, in this step, this was our lumo lowest unoccupied molecular orbital. And this was our homo, the Lewis base. So let's look at the second more closely in terms of energy. So, our homo is the lowest base. It's the highest occupied molecular orbital that has the non bonding pair of electrons. And this is our lumo lowest unoccupied molecular orbital. |
Homo-Lumo interactions.txt | So, our homo is the lowest base. It's the highest occupied molecular orbital that has the non bonding pair of electrons. And this is our lumo lowest unoccupied molecular orbital. It's the two p orbital, and it's a bit higher in energy than our homo. So they interact. They overlap to form our molecular Sigma Bond. |
Homo-Lumo interactions.txt | It's the two p orbital, and it's a bit higher in energy than our homo. So they interact. They overlap to form our molecular Sigma Bond. And the two electrons go into this bonding molecular orbital. And no electrons go into the antibinding molecular orbital because it's higher in energy. So, once again, as an overview, a Lewis acidbased reaction is simply a reaction between a filled orbital of one compound and an empty orbital of second compound. |
Electrolytic cells .txt | Now, electrolytic cells are electrochemical cells that are supplied with an outside source of electrons, which allows reactant favorite redox reactions to occur. Now, recall that voltaic cells convert chemical energy into electrical work via the process of moving electrons in a spontaneous product favorite reaction. So, unlike voltaic cells, electrolytic cells do the opposite. They use up electrical work to power reactant favorite non spontaneous reactions. Now, let's look at an example. Let's look at the decomposition of molten sodium chloride. |
Electrolytic cells .txt | They use up electrical work to power reactant favorite non spontaneous reactions. Now, let's look at an example. Let's look at the decomposition of molten sodium chloride. Now, what molten means is that it's heated to a certain temperature so that it goes from a solid state to a liquid state. This is not an aqueous state. It's a liquid state of sodium chloride, meaning these guys dissociate, but there is no water in our mixture. |
Electrolytic cells .txt | Now, what molten means is that it's heated to a certain temperature so that it goes from a solid state to a liquid state. This is not an aqueous state. It's a liquid state of sodium chloride, meaning these guys dissociate, but there is no water in our mixture. There's no solvent. So let's look at our electrolytic electrochemical cell. So it's composed of not two half cells, but one half cell. |
Electrolytic cells .txt | There's no solvent. So let's look at our electrolytic electrochemical cell. So it's composed of not two half cells, but one half cell. So one beaker. Now, within this beaker, we have melted or liquid sodium chloride. So we have a bunch of sodium molecules or sodium ions chloride ions. |
Electrolytic cells .txt | So one beaker. Now, within this beaker, we have melted or liquid sodium chloride. So we have a bunch of sodium molecules or sodium ions chloride ions. So these two electrodes are in there, so they're made from the same exact material. And what happens is we connect these guards to an outside power source, like a battery or a voltage cell. Now, what happens is this battery powers. |
Electrolytic cells .txt | So these two electrodes are in there, so they're made from the same exact material. And what happens is we connect these guards to an outside power source, like a battery or a voltage cell. Now, what happens is this battery powers. It allows electrons to transfer in this direction. So if they transfer this way, that means this metal obtains these electrons. So this metal or electrode forms a negative charge, while this electrode forms a positive charge, because electrons will be taken away from this electrode. |
Electrolytic cells .txt | It allows electrons to transfer in this direction. So if they transfer this way, that means this metal obtains these electrons. So this metal or electrode forms a negative charge, while this electrode forms a positive charge, because electrons will be taken away from this electrode. So, since this develops a negative charge, let's see what happens with the portion that's immersed into our liquid. Well, we said some of the sodium molecules will be moving around, and since they are positively charged, they will be attracted to this negatively charged electrode. Likewise, these chloride atoms are negatively charged, so they will be attracted to this positively charged electrode. |
Electrolytic cells .txt | So, since this develops a negative charge, let's see what happens with the portion that's immersed into our liquid. Well, we said some of the sodium molecules will be moving around, and since they are positively charged, they will be attracted to this negatively charged electrode. Likewise, these chloride atoms are negatively charged, so they will be attracted to this positively charged electrode. So we'll have a separation of sodium and chloride in our liquid. Now, what happens when our sodium positively charged ion hits this negatively charged electron? Well, some of the electrons will transfer into our sodium molecule, and that means our sodium will be reduced. |
Electrolytic cells .txt | So we'll have a separation of sodium and chloride in our liquid. Now, what happens when our sodium positively charged ion hits this negatively charged electron? Well, some of the electrons will transfer into our sodium molecule, and that means our sodium will be reduced. So this section is where reduction occurs. And that means by definition, it must be our cathode. Now, likewise, when these molecules or ions hit this little electrode, they give off some of these electrons, because electrons want to move from a negative charge to a positive charge. |
Electrolytic cells .txt | So this section is where reduction occurs. And that means by definition, it must be our cathode. Now, likewise, when these molecules or ions hit this little electrode, they give off some of these electrons, because electrons want to move from a negative charge to a positive charge. So when this hits it, electrons travel inside this electrode, and they enter our circuit and travel all the way down here. So what happens when electrons leave? Well, this guy is oxidized into diatomic gas, and so it evaporates into our environment. |
Electrolytic cells .txt | So when this hits it, electrons travel inside this electrode, and they enter our circuit and travel all the way down here. So what happens when electrons leave? Well, this guy is oxidized into diatomic gas, and so it evaporates into our environment. And this is where oxidation takes place. And so, by definition, this guy is our anode. So notice two important differences between voltaic cells and electrolytic cells. |
Electrolytic cells .txt | And this is where oxidation takes place. And so, by definition, this guy is our anode. So notice two important differences between voltaic cells and electrolytic cells. Our cathode in this situation is negative, and our anode is positive. But in voltaic cells, it's reversed. Our cathode is positive and our Amote is negative. |
Electrolytic cells .txt | Our cathode in this situation is negative, and our anode is positive. But in voltaic cells, it's reversed. Our cathode is positive and our Amote is negative. And that's because this electron doesn't travel this way like it does in voltaic cells, but it travels this way due to this outside battery source. Another important difference, obviously, is the fact that in electrolytic cells, we have outside battery source. We have an outside power source. |
Electrolytic cells .txt | And that's because this electron doesn't travel this way like it does in voltaic cells, but it travels this way due to this outside battery source. Another important difference, obviously, is the fact that in electrolytic cells, we have outside battery source. We have an outside power source. But in this will take cells. We don't have it. Now, so let's look at the oxidation reaction that occurs in our anode. |
Electrolytic cells .txt | But in this will take cells. We don't have it. Now, so let's look at the oxidation reaction that occurs in our anode. So two of these molecules, two of these ions give off those two electrons, forming our diatomic gas molecule, and the diatomic gas molecule evaporates into our environment. Now, let's look at a reduction reaction. This reduction reaction occurs in the following manner. |
Electrolytic cells .txt | So two of these molecules, two of these ions give off those two electrons, forming our diatomic gas molecule, and the diatomic gas molecule evaporates into our environment. Now, let's look at a reduction reaction. This reduction reaction occurs in the following manner. Two sodium ions react with two electrons. When they hit this metal, they take up those two electrons, forming two sodium solid molecules or two moles of sodium solid molecules. Now, our net reaction is just an addition of this guy to this guy. |
Electrolytic cells .txt | Two sodium ions react with two electrons. When they hit this metal, they take up those two electrons, forming two sodium solid molecules or two moles of sodium solid molecules. Now, our net reaction is just an addition of this guy to this guy. Notice that electrons cancel, and we simply get the following net reduction reaction. Now, if we were to look up the electron potentials or the cell potentials for this reaction and this reaction, we would get the following voltages. Now, to find the net or the final cell voltage, we simply add these guys up, and we get negative 4.0
72 volts. |
Electrolytic cells .txt | Notice that electrons cancel, and we simply get the following net reduction reaction. Now, if we were to look up the electron potentials or the cell potentials for this reaction and this reaction, we would get the following voltages. Now, to find the net or the final cell voltage, we simply add these guys up, and we get negative 4.0
72 volts. So that means that this much voltage must be supplied to our electrolytic cell by this battery to power this reaction. So decomposition of this guy required energy. Now, other decomposition reactions are very popular. |
Neuron Cells Part I .txt | Well, there are many different examples of concentration cells. Today we're going to look at a very important biological example of a concentration cell called a neuron cell. Now, neuron cells are simply specialized concentration cells found within our nervous system, within our body that communicate with one another via changes in ion concentration. Now, these changes in ion concentration create a difference in voltage or something called a cell voltage. And this difference in voltage creates electrical signals. Now, these electrical signals travel from one cell to another, and this is how cells communicate. |
Neuron Cells Part I .txt | Now, these changes in ion concentration create a difference in voltage or something called a cell voltage. And this difference in voltage creates electrical signals. Now, these electrical signals travel from one cell to another, and this is how cells communicate. Now let's look at something called a resting electrical potential resell. Now, our cells within our body, specifically neuron cells, establish electrical potentials or cell voltages at rest. And what this guy simply means, it's the cell voltage produced by our cell when no signals are being transducted or conducted from one cell to another. |
Neuron Cells Part I .txt | Now let's look at something called a resting electrical potential resell. Now, our cells within our body, specifically neuron cells, establish electrical potentials or cell voltages at rest. And what this guy simply means, it's the cell voltage produced by our cell when no signals are being transducted or conducted from one cell to another. Now let's look at a portion of our cell membrane found at the exxon hillock. The exxon hillock is simply the portion of the neuron where our signal is generated. But remember, we're talking about the resting potential. |
Neuron Cells Part I .txt | Now let's look at a portion of our cell membrane found at the exxon hillock. The exxon hillock is simply the portion of the neuron where our signal is generated. But remember, we're talking about the resting potential. That means no signals are being generated just yet. So let's examine the different types of ions that are present within our body, within our cells. So we see that we have calcium, we have potassium, we have sodium, and we have chloride. |
Neuron Cells Part I .txt | That means no signals are being generated just yet. So let's examine the different types of ions that are present within our body, within our cells. So we see that we have calcium, we have potassium, we have sodium, and we have chloride. Now, when we're at our resting potential, we have a lower concentration of calcium, sodium chloride inside the cell. This is the inside than the outside. On the contrary, we have a higher concentration of potassium ions on the inside than the outside. |
Neuron Cells Part I .txt | Now, when we're at our resting potential, we have a lower concentration of calcium, sodium chloride inside the cell. This is the inside than the outside. On the contrary, we have a higher concentration of potassium ions on the inside than the outside. Now notice we have a semipermandal membrane. So we have hydrophilic heads and hydrophobic tails. These guys are transport membranes or transport proteins. |
Neuron Cells Part I .txt | Now notice we have a semipermandal membrane. So we have hydrophilic heads and hydrophobic tails. These guys are transport membranes or transport proteins. And these proteins allow ions to flow in or as a cell, the active transport or passive transport. Now, so today we're only going to look at this guy here, potassium ion. But notice that our resting electrical potential, the cell or our cell voltage, is generated by simply adding up the cell voltages of all these four ions. |
Neuron Cells Part I .txt | And these proteins allow ions to flow in or as a cell, the active transport or passive transport. Now, so today we're only going to look at this guy here, potassium ion. But notice that our resting electrical potential, the cell or our cell voltage, is generated by simply adding up the cell voltages of all these four ions. When we add all these guys up, we get our final cell voltage or the resting electrical potential. Now, today, to save time, I'm only going to show you for this potassium ion. You can do these on your own. |
Neuron Cells Part I .txt | When we add all these guys up, we get our final cell voltage or the resting electrical potential. Now, today, to save time, I'm only going to show you for this potassium ion. You can do these on your own. So let's take this potassium ion and let's create a concentration cell or a specialized concentration cell called a neuron cell. So this is our electrochemical concentration cell for potassium. This is our negatively charged anode and our positively charged cathode. |
Neuron Cells Part I .txt | So let's take this potassium ion and let's create a concentration cell or a specialized concentration cell called a neuron cell. So this is our electrochemical concentration cell for potassium. This is our negatively charged anode and our positively charged cathode. Now, this is where oxidation of potassium takes place. And this is where reduction of potassium takes place. You could think of this conductor, that electrodes and a sulfbridge, as representing the cell membrane. |
Neuron Cells Part I .txt | Now, this is where oxidation of potassium takes place. And this is where reduction of potassium takes place. You could think of this conductor, that electrodes and a sulfbridge, as representing the cell membrane. And the solution on this in this anode is the outside solution and the cathode is the inside solution. And that's because initially in a concentration cell, this guy is more dilute. That means it's the outside, because remember, we have less potassium on the outside than on the inside. |
Neuron Cells Part I .txt | And the solution on this in this anode is the outside solution and the cathode is the inside solution. And that's because initially in a concentration cell, this guy is more dilute. That means it's the outside, because remember, we have less potassium on the outside than on the inside. So this guy must be the inside. So now let's see what happens. Well, electrons leave this potassium ion or leave the potassium solid ion this electrode and travel via the conductor, via the cell membrane onto this electrode. |
Neuron Cells Part I .txt | So this guy must be the inside. So now let's see what happens. Well, electrons leave this potassium ion or leave the potassium solid ion this electrode and travel via the conductor, via the cell membrane onto this electrode. At the same time, they release these potassium ions into our solution. So the concentration of this guy on the outside becomes greater. Likewise, these guys on the inside here are taken up because they react with the electrons to form our K solid. |
Neuron Cells Part I .txt | At the same time, they release these potassium ions into our solution. So the concentration of this guy on the outside becomes greater. Likewise, these guys on the inside here are taken up because they react with the electrons to form our K solid. And this changes the concentration of our inside and outside. So this is our oxidation reaction, where our potassium is oxidized, and our reduction reaction, where the potassium accepts the electrons form of the solid. Now, if we if we want to find the net rebus reaction, we simply add these two guys up the east cancel, the K solids cancel, and we are left with K plus inside and K plus outside. |
Neuron Cells Part I .txt | And this changes the concentration of our inside and outside. So this is our oxidation reaction, where our potassium is oxidized, and our reduction reaction, where the potassium accepts the electrons form of the solid. Now, if we if we want to find the net rebus reaction, we simply add these two guys up the east cancel, the K solids cancel, and we are left with K plus inside and K plus outside. Notice the reactants is the inside. This is where we begin, and this guy is the outside. This is where we end because electrons travel this way, but the ions want to travel this way because we have more ions on the outside on the inside than the outside. |
Neuron Cells Part I .txt | Notice the reactants is the inside. This is where we begin, and this guy is the outside. This is where we end because electrons travel this way, but the ions want to travel this way because we have more ions on the outside on the inside than the outside. So, once again, in the electrochemical cell setup, electrons travel this way, but C plus atoms travel this way because this concentration increases while this guy decreases. Now, if we look up the cell voltage of this oxidation reaction and this reduction reaction, we find that they're the same magnitude but different signs. So if we add them up, that means they will be zero. |
Calculating the equivalence point .txt | Now, if you don't know what the equivalence point is, check out the link below. So in the beginning, we have a buffer solution of some known asset. So if we know the asset, that means we know the asset amortization constant. We can simply look that up. So in my first step, I basically want to find a KB. And I want to find a KB using this formula here. |
Calculating the equivalence point .txt | We can simply look that up. So in my first step, I basically want to find a KB. And I want to find a KB using this formula here. Now, if you don't know what this formula is or where it comes from, check out the link above and I'll tell you why in a second. We want to find the KB. Well, kw, something we know at some given temperature at a 25 degree celsius, kw is tens of negative 14. |
Calculating the equivalence point .txt | Now, if you don't know what this formula is or where it comes from, check out the link above and I'll tell you why in a second. We want to find the KB. Well, kw, something we know at some given temperature at a 25 degree celsius, kw is tens of negative 14. It's the ionization constant of water. Now, this guy equals ka, something we know times KB. So we find KB by simply dividing kw by ka. |
Calculating the equivalence point .txt | It's the ionization constant of water. Now, this guy equals ka, something we know times KB. So we find KB by simply dividing kw by ka. Now, why do we need the KB? Well, remember what the equivalent point is. It's the point at which all the asset has been neutralized by some base, right? |
Calculating the equivalence point .txt | Now, why do we need the KB? Well, remember what the equivalent point is. It's the point at which all the asset has been neutralized by some base, right? So I can use the KB to find the amount of base needed to neutralize our acid completely. And then if I know my concentration of base, I could find the poh. And using the poh, I can find the PH. |
Calculating the equivalence point .txt | So I can use the KB to find the amount of base needed to neutralize our acid completely. And then if I know my concentration of base, I could find the poh. And using the poh, I can find the PH. And that's exactly what we do. So in my second step, I basically use the KB or the base annette and constant. I equate that to my equilibrium expression, which states that the concentration of hydroxide, what I'm looking for, equals the concentration of the conjugate acid over the concentration of the conjugate base. |
Calculating the equivalence point .txt | And that's exactly what we do. So in my second step, I basically use the KB or the base annette and constant. I equate that to my equilibrium expression, which states that the concentration of hydroxide, what I'm looking for, equals the concentration of the conjugate acid over the concentration of the conjugate base. Now, I could get this guy in this side and divide by this guy and get the concentration that I'm looking at equals a known constant, unknown amount, and a known amount. Now I solve and I find my concentration. Next, I find my poh by using the formula which is negative lot of the concentration found here in step three. |
Calculating the equivalence point .txt | Now, I could get this guy in this side and divide by this guy and get the concentration that I'm looking at equals a known constant, unknown amount, and a known amount. Now I solve and I find my concentration. Next, I find my poh by using the formula which is negative lot of the concentration found here in step three. And finally, in the final step, I solve for that PH by using the formula 14 equals poh plus PH. Now, if you don't know where this formula comes from, check out the link right there. So basically rearrange and find my PH. |
The Cage Effect of Solvents .txt | On average, molecules found in the liquid state collide 100 times more frequently than the same molecules found in the gas state. That means we should be able to assume that reactions occur quicker in the liquid state than in the gas state because reactions require collisions. Now, this is not actually the case, and this is because of an effect called the effect of solvent molecules or Cage effect of solvent molecules. Now let's look at the following reaction. Suppose a red molecule must react with an orange molecule to produce a red orange product. Now, suppose we dissolve these guys in a liquid. |
The Cage Effect of Solvents .txt | Now let's look at the following reaction. Suppose a red molecule must react with an orange molecule to produce a red orange product. Now, suppose we dissolve these guys in a liquid. So in liquid reactants are dissolved in a solvent, like, for example, water, which ends up predominating the solution. Therefore, most of the collisions in liquids occur between solvent and solute. And this means that even though the collisions occur more frequently in liquid than acoustic solutions, a lot of those collisions are between solvent and soluble molecules. |
The Cage Effect of Solvents .txt | So in liquid reactants are dissolved in a solvent, like, for example, water, which ends up predominating the solution. Therefore, most of the collisions in liquids occur between solvent and solute. And this means that even though the collisions occur more frequently in liquid than acoustic solutions, a lot of those collisions are between solvent and soluble molecules. And the only way you react molecules is if the reactive molecules react. So, because most of the collisions occur between solid molecules and solid molecules, that means, on average, reactions in the gas state and liquid state will be approximately the same. Now let's look at this Cage effect. |
The Cage Effect of Solvents .txt | And the only way you react molecules is if the reactive molecules react. So, because most of the collisions occur between solid molecules and solid molecules, that means, on average, reactions in the gas state and liquid state will be approximately the same. Now let's look at this Cage effect. Suppose we have our system where the red molecules are water solid molecules and the red and orange molecules or the molecules spoken about here, are the reactants. So notice that the red molecule is in a cage of solid molecules and before it leaves, they make many collisions with the water cage. Eventually, however, it will bounce out. |
The Cage Effect of Solvents .txt | Suppose we have our system where the red molecules are water solid molecules and the red and orange molecules or the molecules spoken about here, are the reactants. So notice that the red molecule is in a cage of solid molecules and before it leaves, they make many collisions with the water cage. Eventually, however, it will bounce out. And if it bounces into another cage where this origin molecule is present, then it will react to former products. But otherwise, if it jumps into another cage that doesn't have another reactor molecule, it will continue balancing. And this greatly slows down our reaction in liquid and increased space. |
Carbon Dioxide vs Water Phase Diagrams .txt | Second the X axis is temperature. Now two main differences exist between the two phase diagrams. First at one atmospheric pressure. Water exists in all three phases. However, for the carbon dioxide diagram, we see that carbon dioxide exists only in the solid phase and in the gas days. Let's look at the water diagram first. |
Carbon Dioxide vs Water Phase Diagrams .txt | Water exists in all three phases. However, for the carbon dioxide diagram, we see that carbon dioxide exists only in the solid phase and in the gas days. Let's look at the water diagram first. So at low temperatures, from here to here, we can find water in the solid state. At medium temperatures, from here to here, we can find water in the liquid state. And finally, at high temperatures above this temperature, we can find water in the gas state. |
Carbon Dioxide vs Water Phase Diagrams .txt | So at low temperatures, from here to here, we can find water in the solid state. At medium temperatures, from here to here, we can find water in the liquid state. And finally, at high temperatures above this temperature, we can find water in the gas state. For carbon dioxide. However, at one ATM, at low temperatures, below this temperature, we find that in the solid base and then we see that above this temperature, our solid sublons directly into the gas state. And so we could only find carbon dioxide in a solid and gas state at 180 m. The only way we could get into the liquid state is if we increase pressure and then increase temperature. |
Carbon Dioxide vs Water Phase Diagrams .txt | For carbon dioxide. However, at one ATM, at low temperatures, below this temperature, we find that in the solid base and then we see that above this temperature, our solid sublons directly into the gas state. And so we could only find carbon dioxide in a solid and gas state at 180 m. The only way we could get into the liquid state is if we increase pressure and then increase temperature. The second main difference, and perhaps the more important difference, is the following. For the phase diagram of water. The boundary between the solid and the liquid line. |
Carbon Dioxide vs Water Phase Diagrams .txt | The second main difference, and perhaps the more important difference, is the following. For the phase diagram of water. The boundary between the solid and the liquid line. This line has a negative slope. While for the carbon dioxide phase diagram, the boundary between the solid and liquid is positive. It has a positive slope. |
Carbon Dioxide vs Water Phase Diagrams .txt | This line has a negative slope. While for the carbon dioxide phase diagram, the boundary between the solid and liquid is positive. It has a positive slope. So it's increasing here. And it's decreasing here. And this happens because water has special properties. |
Carbon Dioxide vs Water Phase Diagrams .txt | So it's increasing here. And it's decreasing here. And this happens because water has special properties. As a solid. The molecules in the solid states are very far apart or further apart than they are in the liquid water states. And that means liquid. |
Carbon Dioxide vs Water Phase Diagrams .txt | As a solid. The molecules in the solid states are very far apart or further apart than they are in the liquid water states. And that means liquid. The molecules are closer. So for some given volume water, liquid or liquid water is more dense than solid water. And that's why ice states a float. |
Carbon Dioxide vs Water Phase Diagrams .txt | The molecules are closer. So for some given volume water, liquid or liquid water is more dense than solid water. And that's why ice states a float. Because ice is less dense than water. So for this guy, however, the solid is more dense than the liquid, and therefore, this slope is positive. So if you place a solid carbon dioxide into the liquid, it's going to sink straight down. |
Carbon Dioxide vs Water Phase Diagrams .txt | Because ice is less dense than water. So for this guy, however, the solid is more dense than the liquid, and therefore, this slope is positive. So if you place a solid carbon dioxide into the liquid, it's going to sink straight down. Now, one more effect because of this negative slope is the following Because the slope is negative. If we keep our temperature constant, say, somewhere right here. So if we keep this temperature constant, we see that we can actually make the solid become a liquid by simply increasing our pressure. |
Carbon Dioxide vs Water Phase Diagrams .txt | Now, one more effect because of this negative slope is the following Because the slope is negative. If we keep our temperature constant, say, somewhere right here. So if we keep this temperature constant, we see that we can actually make the solid become a liquid by simply increasing our pressure. So at constant temperature, we can make a solid become a liquid by simply compressing it, increasing the pressure. But for this situation, we can't. The only way we get a solid to become a liquid is if we increase temperature. |
Phase Change of Water .txt | In this lecture, we're going to look at the phase change of water at constant pressure at one ATM when it goes from a very low temperature to a very high temperature. So the Y axis is temperature in Celsius. The X axis is energy input. And Joules, let's begin at negative 60 Celsius. So we want to go from negative negative 60 celsius to zero celsius. And we do so by heating our system. |
Phase Change of Water .txt | And Joules, let's begin at negative 60 Celsius. So we want to go from negative negative 60 celsius to zero celsius. And we do so by heating our system. So what happens on a microscopic level when we heat the system? Well, on a microscopic level, we increase the kinetic energy of our molecules because kinetic energy is what's responsible for increasing temperature. So our potential energy stays the same from this point to this point. |
Phase Change of Water .txt | So what happens on a microscopic level when we heat the system? Well, on a microscopic level, we increase the kinetic energy of our molecules because kinetic energy is what's responsible for increasing temperature. So our potential energy stays the same from this point to this point. But our kinetic energy increases. Now, when we get to zero degrees Celsius, a phase change occurs. So solid becomes a liquid and the change in temperature notice is zero. |
Phase Change of Water .txt | But our kinetic energy increases. Now, when we get to zero degrees Celsius, a phase change occurs. So solid becomes a liquid and the change in temperature notice is zero. So the slope is zero. So from this point to this point, the temperature is the same. It's zero degrees Celsius. |
Phase Change of Water .txt | So the slope is zero. So from this point to this point, the temperature is the same. It's zero degrees Celsius. And that's because all the energy input goes into increasing potential energy of our substance. And potential energy increase is what causes the change in phase. When we finish the phase change, we want to increase temperature once again. |
Phase Change of Water .txt | And that's because all the energy input goes into increasing potential energy of our substance. And potential energy increase is what causes the change in phase. When we finish the phase change, we want to increase temperature once again. So once again, all the energy input goes into increasing our kinetic energy of our molecules. Because kinetic energy is what's responsible for increasing temperature. So when we get to 100 degrees Celsius, once again, our slope is zero. |
Phase Change of Water .txt | So once again, all the energy input goes into increasing our kinetic energy of our molecules. Because kinetic energy is what's responsible for increasing temperature. So when we get to 100 degrees Celsius, once again, our slope is zero. That means our temperature change is zero. All the energy goes into increasing potential energy of our bonds found within the liquid and gas phase. So eventually all the liquid becomes gas. |
Phase Change of Water .txt | That means our temperature change is zero. All the energy goes into increasing potential energy of our bonds found within the liquid and gas phase. So eventually all the liquid becomes gas. And once again, we follow a linear graph here. So any increase in energy will increase kinetic energy of our molecules. So, once again, let's review. |
Phase Change of Water .txt | And once again, we follow a linear graph here. So any increase in energy will increase kinetic energy of our molecules. So, once again, let's review. So when the slope is zero, we deal with phase changes. And here all energy input goes into increasing potential energy of the system. No change in kinetic energy is observed. |
Phase Change of Water .txt | So when the slope is zero, we deal with phase changes. And here all energy input goes into increasing potential energy of the system. No change in kinetic energy is observed. And so the change in temperature in both cases is zero. When we talk about going from this guy to this guy or from this guy to this guy, the intermediate phases between the phase changes, we talk about energy input that goes into increasing kinetic energy of the system because kinetic energy of the system is what increases temperature. Because we want to go from zero to 100 and from negative 60 to zero. |
Phase Change of Water .txt | And so the change in temperature in both cases is zero. When we talk about going from this guy to this guy or from this guy to this guy, the intermediate phases between the phase changes, we talk about energy input that goes into increasing kinetic energy of the system because kinetic energy of the system is what increases temperature. Because we want to go from zero to 100 and from negative 60 to zero. We want to increase temperature and not the potential energy of the system. So let's talk about one last thing. So when we go from solid to liquid, that's called melting. |
Phase Change of Water .txt | We want to increase temperature and not the potential energy of the system. So let's talk about one last thing. So when we go from solid to liquid, that's called melting. Okay? And melting according to this graph is endothermic. And that's because our final energy level is somewhere here. |