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Raoul’s Law for Ideal Fluids .txt | The system is said to be in dynamic equilibrium. At this point, we could measure something called vapor pressure. Vapor pressure is the pressure exerted by evaporating molecules or gas molecules found in dynamic equilibrium with the pure liquid molecules. Now, what will happen to our system if we add a non volatile compound to our pure substance? Remember, a non volatile compound is a compound that will not evaporate. And remember, evaporation only occurs on the surface area of the liquid. |
Raoul’s Law for Ideal Fluids .txt | Now, what will happen to our system if we add a non volatile compound to our pure substance? Remember, a non volatile compound is a compound that will not evaporate. And remember, evaporation only occurs on the surface area of the liquid. So therefore, let's look at what happens to our surface area after we add this substance. The surface area of the liquid is constant, it remains the same. And that's because our system, our container, remains constant. |
Raoul’s Law for Ideal Fluids .txt | So therefore, let's look at what happens to our surface area after we add this substance. The surface area of the liquid is constant, it remains the same. And that's because our system, our container, remains constant. It will not change in shape or size. So if you take the crosssectional before addition and after addition, the crosssectional area will remain the same. What will change however, is the number of pure liquid molecules found on the surface area and this number will decrease. |
Raoul’s Law for Ideal Fluids .txt | It will not change in shape or size. So if you take the crosssectional before addition and after addition, the crosssectional area will remain the same. What will change however, is the number of pure liquid molecules found on the surface area and this number will decrease. And this is because of the presence of nonvolatile compounds. Now for example, let's look at the before picture. Before addition, we have water molecules found on the surface area. |
Raoul’s Law for Ideal Fluids .txt | And this is because of the presence of nonvolatile compounds. Now for example, let's look at the before picture. Before addition, we have water molecules found on the surface area. And these water molecules will escape and they're going to condense back into the liquid state. Now, after the addition, we're going to have some non volatile compounds replacing these molecules. And that means less molecules or less pure molecules present on the surface. |
Raoul’s Law for Ideal Fluids .txt | And these water molecules will escape and they're going to condense back into the liquid state. Now, after the addition, we're going to have some non volatile compounds replacing these molecules. And that means less molecules or less pure molecules present on the surface. And remember, evaporation occurs on the surface of the liquid. So there are less volatile molecules, less molecules that evaporate, less gas molecules will be present at equilibrium. And this means the pressure of the vapor pressure is less. |
Raoul’s Law for Ideal Fluids .txt | And remember, evaporation occurs on the surface of the liquid. So there are less volatile molecules, less molecules that evaporate, less gas molecules will be present at equilibrium. And this means the pressure of the vapor pressure is less. And this is Rolls law. Rolt's law gives us the following equation. The vapor pressure after the addition is equal to the mole fraction of the pure substance times the vapor pressure before addition. |
Raoul’s Law for Ideal Fluids .txt | And this is Rolls law. Rolt's law gives us the following equation. The vapor pressure after the addition is equal to the mole fraction of the pure substance times the vapor pressure before addition. And this is known as Rolls law. Now let's look at the addition of a volatile compound to a pure mixture. A volatile compound is simply a compound that will evaporate. |
Raoul’s Law for Ideal Fluids .txt | And this is known as Rolls law. Now let's look at the addition of a volatile compound to a pure mixture. A volatile compound is simply a compound that will evaporate. So what happens to our surface area? Well, the surface area remains the same, and that's because once again, our container does not change in shape or size. Its cross sectional area remains constant. |
Raoul’s Law for Ideal Fluids .txt | So what happens to our surface area? Well, the surface area remains the same, and that's because once again, our container does not change in shape or size. Its cross sectional area remains constant. And once again, we have a less pure molecules found on the surface. And that's because they're replaced by the new volatile content. But now there's a major difference. |
Raoul’s Law for Ideal Fluids .txt | And once again, we have a less pure molecules found on the surface. And that's because they're replaced by the new volatile content. But now there's a major difference. Now we're dealing with a content that is allowed to evaporate. So let's look at the difference. The before picture, before addition, we only have water molecules or pure molecules found on a surface. |
Raoul’s Law for Ideal Fluids .txt | Now we're dealing with a content that is allowed to evaporate. So let's look at the difference. The before picture, before addition, we only have water molecules or pure molecules found on a surface. And these guys will evaporate and will create a certain vapor pressure. The vapor pressure is this the after picture? After we add the volatile compound, we're going to have a mixture of the new compound and the old compound found on the surface area. |
Raoul’s Law for Ideal Fluids .txt | And these guys will evaporate and will create a certain vapor pressure. The vapor pressure is this the after picture? After we add the volatile compound, we're going to have a mixture of the new compound and the old compound found on the surface area. But now the red guys, the new compound, are allowed to evaporate. So now the vapor pressure will be due to these molecules and these molecules. So Roth's law will tell us that the final vapor pressure of our system will be the vapor pressure due to the new guys, plus the vapor pressure due to the old guys. |
Osmosis and Osmotic Pressure.txt | So if you're not sure about entropy, check out the link below. So one of the most basic definitions of entropy is that entropy is the tendency of a system to even out. For example, let's look at system. This system is composed of two sections connected by a bridge and we have two molecules on this side and eight molecules on this side. What entropy tells us is that eventually three of these molecules will end up on this side and that this system will be the most probable system. So we want a system that's even not uneven or balanced, not on balance, in which we have five molecules here and five molecules here. |
Osmosis and Osmotic Pressure.txt | This system is composed of two sections connected by a bridge and we have two molecules on this side and eight molecules on this side. What entropy tells us is that eventually three of these molecules will end up on this side and that this system will be the most probable system. So we want a system that's even not uneven or balanced, not on balance, in which we have five molecules here and five molecules here. Let's look at system C.
Now, in system C we basically have a cell. And this cell is surrounded by semipermeable membrane that allows water molecules in and out but does not allow any size molecules to go in or out. Now, in this cell, however, we have a small hole in the membrane and this hole is large enough to allow the molecules in and out. |
Osmosis and Osmotic Pressure.txt | Let's look at system C.
Now, in system C we basically have a cell. And this cell is surrounded by semipermeable membrane that allows water molecules in and out but does not allow any size molecules to go in or out. Now, in this cell, however, we have a small hole in the membrane and this hole is large enough to allow the molecules in and out. So water is going to travel in and out and so will the molecules. So eventually, according to what entropy tells us, we're going to want to go from system C to system D. That is, we want to travel from this system to this even system in which we have five molecules on this side on the inside and five molecules on the outside. Now let's look at a third system. |
Osmosis and Osmotic Pressure.txt | So water is going to travel in and out and so will the molecules. So eventually, according to what entropy tells us, we're going to want to go from system C to system D. That is, we want to travel from this system to this even system in which we have five molecules on this side on the inside and five molecules on the outside. Now let's look at a third system. Let's look at system E. Now, in system E, we basically have the same system as above, except now our hole is filled in. So we have a continuous circular membrane. So now we can't talk about the side molecules going in and out because side molecules can't go in and out. |
Osmosis and Osmotic Pressure.txt | Let's look at system E. Now, in system E, we basically have the same system as above, except now our hole is filled in. So we have a continuous circular membrane. So now we can't talk about the side molecules going in and out because side molecules can't go in and out. And that's because of the membrane. The membrane is a barrier to the side molecules. So we must talk about something else. |
Osmosis and Osmotic Pressure.txt | And that's because of the membrane. The membrane is a barrier to the side molecules. So we must talk about something else. We must talk about the amount of solid molecules per some given volume. And in fact, that's concentration. So our concentration on the outside, because we have more molecules, is higher than the concentration on the inside. |
Osmosis and Osmotic Pressure.txt | We must talk about the amount of solid molecules per some given volume. And in fact, that's concentration. So our concentration on the outside, because we have more molecules, is higher than the concentration on the inside. So what will happen? Well, entropy tells us that in this case, the only thing that can move, which is a solvent and the water will move and water will travel from the inside to the outside. So our cell will shrink in size and our concentration will increase in size because now we have less volume. |
Osmosis and Osmotic Pressure.txt | So what will happen? Well, entropy tells us that in this case, the only thing that can move, which is a solvent and the water will move and water will travel from the inside to the outside. So our cell will shrink in size and our concentration will increase in size because now we have less volume. But the same amount of solution, now the concentration on the outside will decrease because now we have the same amount, but a larger volume, a larger amount of water. And that means eventually our concentrations will equal out. So now let's define osmosis. |
Osmosis and Osmotic Pressure.txt | But the same amount of solution, now the concentration on the outside will decrease because now we have the same amount, but a larger volume, a larger amount of water. And that means eventually our concentrations will equal out. So now let's define osmosis. Osmosis is the movement of solvent. In our case, water from an area of a lower side concentration to an area of a higher sized concentration. So in the system above, osmosis occurred from the inside the cell into the outside, because water moves from a lower concentration to a higher concentration. |
Osmosis and Osmotic Pressure.txt | Osmosis is the movement of solvent. In our case, water from an area of a lower side concentration to an area of a higher sized concentration. So in the system above, osmosis occurred from the inside the cell into the outside, because water moves from a lower concentration to a higher concentration. Okay? Now, we can also talk about something called osmotic pressure. Osmotic pressure is the pressure required to stop osmosis. |
Osmosis and Osmotic Pressure.txt | Okay? Now, we can also talk about something called osmotic pressure. Osmotic pressure is the pressure required to stop osmosis. So, for example, suppose we apply some pressure to our cell membrane, and if this pressure equals asthmatic pressure, well, then no osmosis will occur, no movement of water will occur. And this becomes very important when you're talking about hydrostatic pressure and asthmatic pressure in the capillaries of our body. So the last thing I want to talk about is a formula. |
Osmosis and Osmotic Pressure.txt | So, for example, suppose we apply some pressure to our cell membrane, and if this pressure equals asthmatic pressure, well, then no osmosis will occur, no movement of water will occur. And this becomes very important when you're talking about hydrostatic pressure and asthmatic pressure in the capillaries of our body. So the last thing I want to talk about is a formula. And this formula could be only used when we talk about ideal conditions. So ideal solutions and solutions that have very low or small concentrations. Now, if you want to look at a problem using this formula, check out the link below. |
Osmosis and Osmotic Pressure.txt | And this formula could be only used when we talk about ideal conditions. So ideal solutions and solutions that have very low or small concentrations. Now, if you want to look at a problem using this formula, check out the link below. Now let's look at the formula. The formula basically states that osmotic pressure is equal to molarity of solution times our gas constants r times our temperature in Kelvin times I. Now, I is called a vant half factor. |
Methyl Compounds .txt | So let's discuss methyl compounds. Now, methyl compounds are simply compounds that have a side chain or side group ch three. And that ch three is attached covalently to some other atomyl chloride compound given here, x. Now, this x could be anything, and here are a few examples. We have methyl chloride, methyl alcohol, or methanol. We have methylamine, and we have methylcyanide. |
Methyl Compounds .txt | Now, this x could be anything, and here are a few examples. We have methyl chloride, methyl alcohol, or methanol. We have methylamine, and we have methylcyanide. So let's compare methyl compounds to something that we already spoke about methane. In fact, methane is methyl compound where the x has been replaced with an H. Now, methane is the simplest alkane, and methane has symmetry. And that's because the carbon, the central carbon, is attached to four identical H atoms, 1234. |
Methyl Compounds .txt | So let's compare methyl compounds to something that we already spoke about methane. In fact, methane is methyl compound where the x has been replaced with an H. Now, methane is the simplest alkane, and methane has symmetry. And that's because the carbon, the central carbon, is attached to four identical H atoms, 1234. And that means all the ch bonds will be exactly the same as the other. All these ch bonds will be SP three hybridized, and the angles between a two bonds will be 109.5
degrees. So, once again, each bond is identical because we have a single carbon atom attached to four identical H atoms. |
Methyl Compounds .txt | And that means all the ch bonds will be exactly the same as the other. All these ch bonds will be SP three hybridized, and the angles between a two bonds will be 109.5
degrees. So, once again, each bond is identical because we have a single carbon atom attached to four identical H atoms. Hence, our bonds are all SP three hybridized. So let's take this methane and compare it to a methylcogddam. So here we have a methylcogdam, where we replace the H with an x. |
Methyl Compounds .txt | Hence, our bonds are all SP three hybridized. So let's take this methane and compare it to a methylcogddam. So here we have a methylcogdam, where we replace the H with an x. This X could be any atom. Now, we have bonds that are not all identical. In other words, we still have three of these ch bonds, but now we have a different CX bond. |
Methyl Compounds .txt | This X could be any atom. Now, we have bonds that are not all identical. In other words, we still have three of these ch bonds, but now we have a different CX bond. For example, if I replace this x with a chloride atom, so this is a chloride. That means the chloride, since the chloride is more electronegative than either the carbon or the H atoms, that means that chloride will pull electrons more strongly than either of the H atom. And so there will be an unequal electron density in this bond. |
Methyl Compounds .txt | For example, if I replace this x with a chloride atom, so this is a chloride. That means the chloride, since the chloride is more electronegative than either the carbon or the H atoms, that means that chloride will pull electrons more strongly than either of the H atom. And so there will be an unequal electron density in this bond. Electrons will be closer to this x atom, to this CL atom than to the carbon atom. And that means that this will be a slightly asymmetrical molecule, asymmetrical compound. And so it will slightly deviate from this methane compound. |
Class Clapeyron Example .txt | So we are given alcohol, and we know that our alcohol at 20 degrees Celsius has a vapor pressure of 40 mercury. And at 61 degrees Celsius, it has a vapor pressure of 360 millimeters of mercury. And our goal is to find a change in entropy of vaporization of 1 mol of alcohol. So to find that, we have to use something called a class here to clay for an equation. Now, if you want to learn more about this equation, where it comes from, and why it's important, check out the link below. So let's look at our equation. |
Class Clapeyron Example .txt | So to find that, we have to use something called a class here to clay for an equation. Now, if you want to learn more about this equation, where it comes from, and why it's important, check out the link below. So let's look at our equation. Notice that in this equation we have three knowns and two unknowns. So we have a constant R, it's a gas constant. We know that. |
Class Clapeyron Example .txt | Notice that in this equation we have three knowns and two unknowns. So we have a constant R, it's a gas constant. We know that. Now we have the pressure and we have a temperature. What we don't have is this C constant and this entropy of vaporization. In fact, that's exactly what we want to find. |
Class Clapeyron Example .txt | Now we have the pressure and we have a temperature. What we don't have is this C constant and this entropy of vaporization. In fact, that's exactly what we want to find. So if we somehow know this, we can find that. But an even better tactic would be to get rid of this. So notice we have a single equation and two unknowns. |
Class Clapeyron Example .txt | So if we somehow know this, we can find that. But an even better tactic would be to get rid of this. So notice we have a single equation and two unknowns. So mathematically we can't solve this. But if we come up with a system of equations, two equations and two unknowns, we could somehow manipulate the two equations, get rid of that C, and solve for our unknown. And in fact, that's exactly what we're going to do. |
Class Clapeyron Example .txt | So mathematically we can't solve this. But if we come up with a system of equations, two equations and two unknowns, we could somehow manipulate the two equations, get rid of that C, and solve for our unknown. And in fact, that's exactly what we're going to do. Notice we have initial conditions and final conditions. So why not come up with two of these equations, one for the initial condition and one for the final condition. That's exactly what we do here. |
Class Clapeyron Example .txt | Notice we have initial conditions and final conditions. So why not come up with two of these equations, one for the initial condition and one for the final condition. That's exactly what we do here. This one is for our final conditions, where PF and TF are P final and T final. And this guy is for our initial conditions, p initial and T initial. And in order to get rid of these two C's, let's subtract this guy from this guy. |
Class Clapeyron Example .txt | This one is for our final conditions, where PF and TF are P final and T final. And this guy is for our initial conditions, p initial and T initial. And in order to get rid of these two C's, let's subtract this guy from this guy. Okay, that's exactly what we do right here. So this guy minus this guy. Now notice we have the equal sign here. |
Class Clapeyron Example .txt | Okay, that's exactly what we do right here. So this guy minus this guy. Now notice we have the equal sign here. We're going to subtract everything on this side first, then everything on this side next. So natural log of P final, minus natural log of P initial, and we get exactly this. Next, we subtract this whole section from this whole section. |
Class Clapeyron Example .txt | We're going to subtract everything on this side first, then everything on this side next. So natural log of P final, minus natural log of P initial, and we get exactly this. Next, we subtract this whole section from this whole section. So first we take this and we put it here. That's exactly what we did. Next, we subtract this guy from this guy. |
Class Clapeyron Example .txt | So first we take this and we put it here. That's exactly what we did. Next, we subtract this guy from this guy. But notice we have a negative sign here, and that means we have to distribute this negative sign to here and here. So this guy becomes positive. So we get plus this guy, and this negative makes this positive a negative. |
Class Clapeyron Example .txt | But notice we have a negative sign here, and that means we have to distribute this negative sign to here and here. So this guy becomes positive. So we get plus this guy, and this negative makes this positive a negative. So this guy becomes a negative. And now notice we have a plus C and a minus C. So the C's cancel and we get just this guy plus this guy. And that's exactly what we have right here. |
Class Clapeyron Example .txt | So this guy becomes a negative. And now notice we have a plus C and a minus C. So the C's cancel and we get just this guy plus this guy. And that's exactly what we have right here. Now our next step is to basically equate this guy, to simply this guy and rewrite the equations to a better looking formula so this guy, using the logs of logs, we can rewrite in this format. So natural log of P final divided by P initial equals. Now, notice on this side, we have two common terms or one common term. |
Class Clapeyron Example .txt | Now our next step is to basically equate this guy, to simply this guy and rewrite the equations to a better looking formula so this guy, using the logs of logs, we can rewrite in this format. So natural log of P final divided by P initial equals. Now, notice on this side, we have two common terms or one common term. This guy and this guy are two of the same term. It's the same term. So basically, you want to take this guy out of our equation and leave this guy and this guy alone. |
Class Clapeyron Example .txt | This guy and this guy are two of the same term. It's the same term. So basically, you want to take this guy out of our equation and leave this guy and this guy alone. So negative change in anthropy vaporization over r, our common term, times one over t, final minus one over T initial. Notice that here this was a positive. But since we're taking a negative out, this becomes a negative. |
Class Clapeyron Example .txt | So negative change in anthropy vaporization over r, our common term, times one over t, final minus one over T initial. Notice that here this was a positive. But since we're taking a negative out, this becomes a negative. And to check that, we multiply this out and we should get this form. And, in fact, we do. Now, our final step before we plug in chug is simply to rewrite this so that we have this thing on one side and everything else, all the knowns on the other side. |
Class Clapeyron Example .txt | And to check that, we multiply this out and we should get this form. And, in fact, we do. Now, our final step before we plug in chug is simply to rewrite this so that we have this thing on one side and everything else, all the knowns on the other side. So you want the unknown on one side and the knowns on the other side. And this is what we get. So what we do is we find the common denominator here, multiply this by Ti and this by TF, bring everything over, bring the R over, and then bring the negative over, and we get this. |
Class Clapeyron Example .txt | So you want the unknown on one side and the knowns on the other side. And this is what we get. So what we do is we find the common denominator here, multiply this by Ti and this by TF, bring everything over, bring the R over, and then bring the negative over, and we get this. Finally, we plug in all our information. So our R, it's 8.31
joules per mole times Kelvin, times natural log of 360 or 40, which is simply nine times. Now, we have to use our temperature in Kelvin, and that means we have to convert from celebrates to Kelvin by simply adding 273 to each temperature. |
Class Clapeyron Example .txt | Finally, we plug in all our information. So our R, it's 8.31
joules per mole times Kelvin, times natural log of 360 or 40, which is simply nine times. Now, we have to use our temperature in Kelvin, and that means we have to convert from celebrates to Kelvin by simply adding 273 to each temperature. So this is what we get. We basically plug this into our calculator. We solve, and we get approximately 44 kilojoules per mole. |
Alkenes and Double Bonds .txt | But unlike alkanes, alkines contain a double bond. And in this lecture, we're going to examine exactly what a double bond is. So let's begin by looking at the simplest alkhine, known as ethylene, also known as ethylene. Now, ethylene is composed of two carbons connected by a double bond and two H atoms found on both sides of those carbons. So let's begin by building or creating this ethylene molecule. So let's create it using a methylratical. |
Alkenes and Double Bonds .txt | Now, ethylene is composed of two carbons connected by a double bond and two H atoms found on both sides of those carbons. So let's begin by building or creating this ethylene molecule. So let's create it using a methylratical. Recall that a methylradical is simply a carbon atom attached to three H bonds or three H atoms via SP two hybridized orbitals. So each of these sigma bonds, covalent sigma bonds, are SP two hybridized. And we also have a pure two p orbital that contains a single electron within that two p orbital. |
Alkenes and Double Bonds .txt | Recall that a methylradical is simply a carbon atom attached to three H bonds or three H atoms via SP two hybridized orbitals. So each of these sigma bonds, covalent sigma bonds, are SP two hybridized. And we also have a pure two p orbital that contains a single electron within that two p orbital. So, to build this ethylene, let's simply replace the H atom here with a methylene atom with a ch two atom, or a ch two molecule. Sorry. What do we get? |
Alkenes and Double Bonds .txt | So, to build this ethylene, let's simply replace the H atom here with a methylene atom with a ch two atom, or a ch two molecule. Sorry. What do we get? Well, if we say if we replace this with a ch two molecule, we get the following picture. So, we get a carbon carbon bond. We get four PH bonds, two on each side. |
Alkenes and Double Bonds .txt | Well, if we say if we replace this with a ch two molecule, we get the following picture. So, we get a carbon carbon bond. We get four PH bonds, two on each side. And we have a two p orbital on both of these carbons that has an electron in each orbital. So first, we let's examine what type of bond this carbon carbon bond is. So this carbon donates an SP two hybridized orbital. |
Alkenes and Double Bonds .txt | And we have a two p orbital on both of these carbons that has an electron in each orbital. So first, we let's examine what type of bond this carbon carbon bond is. So this carbon donates an SP two hybridized orbital. Remember, these guys are SP two hybridized. And this carbon also donates an SP two hybridized orbital. So when we combine two atomic orbitals, we must form two molecular orbitals according to quantum mechanics. |
Alkenes and Double Bonds .txt | Remember, these guys are SP two hybridized. And this carbon also donates an SP two hybridized orbital. So when we combine two atomic orbitals, we must form two molecular orbitals according to quantum mechanics. And so our lower end energy more stable molecular orbital will be due to the overlap of these green regions. And we will get the following SP two, SP two sigma bonding molecular orbital, or simply mo. So the two electrons, one electron in each of this carbon in each of these SP two hybridized orbitals will go into this lower in energy bonding molecular orbital. |
Alkenes and Double Bonds .txt | And so our lower end energy more stable molecular orbital will be due to the overlap of these green regions. And we will get the following SP two, SP two sigma bonding molecular orbital, or simply mo. So the two electrons, one electron in each of this carbon in each of these SP two hybridized orbitals will go into this lower in energy bonding molecular orbital. Now, we're also going to have this antibonding molecular orbital. But since it's high in energy and it's morphed and it's less stable, the electrons will not go into that orbital. So both electrons will be in this molecular orbital. |
Alkenes and Double Bonds .txt | Now, we're also going to have this antibonding molecular orbital. But since it's high in energy and it's morphed and it's less stable, the electrons will not go into that orbital. So both electrons will be in this molecular orbital. And so this covalent bond is SP two SP two hybridized sigma bonding molecular orbital. And now notice one more thing. Notice we have these two two p orbitals, and they're both parallel to one another. |
Alkenes and Double Bonds .txt | And so this covalent bond is SP two SP two hybridized sigma bonding molecular orbital. And now notice one more thing. Notice we have these two two p orbitals, and they're both parallel to one another. In other words, these two guides are parallel to one another, and they're perpendicular to either of these ch bonds. And so, because these guides are parallel and because they have the same exact energy as one another, they will create an overlapping condition. So, once again, just like we have an overlap here, we're going to have an overlap here. |
Alkenes and Double Bonds .txt | In other words, these two guides are parallel to one another, and they're perpendicular to either of these ch bonds. And so, because these guides are parallel and because they have the same exact energy as one another, they will create an overlapping condition. So, once again, just like we have an overlap here, we're going to have an overlap here. So let's combine these two p orbitals. So here we have a two p orbital from this carbon combined with a two P orbital from this carbon. Once again, we're combining two atomic orbitals to form two different molecular orbitals. |
Alkenes and Double Bonds .txt | So let's combine these two p orbitals. So here we have a two p orbital from this carbon combined with a two P orbital from this carbon. Once again, we're combining two atomic orbitals to form two different molecular orbitals. However, now they're no longer Sigma. They're called pi. Okay? |
Alkenes and Double Bonds .txt | However, now they're no longer Sigma. They're called pi. Okay? So one is a pi, or two P, two pi bonding molecular orbital. And the second one is a two P two pi antibonding molecular orbital. So, there will be one known between these two orbitals. |
Alkenes and Double Bonds .txt | So one is a pi, or two P, two pi bonding molecular orbital. And the second one is a two P two pi antibonding molecular orbital. So, there will be one known between these two orbitals. And that means this guy will be higher in energy and less stable. And so electrons will tend to go into the lower in energy more stable bond. So this pi bond here. |
Alkenes and Double Bonds .txt | And that means this guy will be higher in energy and less stable. And so electrons will tend to go into the lower in energy more stable bond. So this pi bond here. Now, notice one difference between our Sigma and our Pi bonds. Both of these SP two hybridized orbitals contain 33% or 33.3% as character, while these two p orbitals contain no as character. So that means, because these guys contain the more stable S character, these are more stable. |
Alkenes and Double Bonds .txt | Now, notice one difference between our Sigma and our Pi bonds. Both of these SP two hybridized orbitals contain 33% or 33.3% as character, while these two p orbitals contain no as character. So that means, because these guys contain the more stable S character, these are more stable. So that means they're lower in energy than these two P orbitals. So when these two orbitals, when these two p orbitals combine to form a pi orbital, this pi orbital is higher in energy than this SP two SP two Sigma bonding molecular orbital. And that means this will be more stable than our Pi bond. |
Alkenes and Double Bonds .txt | So that means they're lower in energy than these two P orbitals. So when these two orbitals, when these two p orbitals combine to form a pi orbital, this pi orbital is higher in energy than this SP two SP two Sigma bonding molecular orbital. And that means this will be more stable than our Pi bond. So now let's redraw our diagram for this silent molecule. So here we have our two carbons, and they create an SP two hybridized molecular orbital given here. And it also creates this interaction here between our pure two P orbitals. |
Alkenes and Double Bonds .txt | So now let's redraw our diagram for this silent molecule. So here we have our two carbons, and they create an SP two hybridized molecular orbital given here. And it also creates this interaction here between our pure two P orbitals. Remember, this electron is found at the same time in this region, as well as in this region. So that means there will be interaction between these two lobes here. And so this is known as our Pi bond, and this is known as our Sigma Bond. |
Alkenes and Double Bonds .txt | Remember, this electron is found at the same time in this region, as well as in this region. So that means there will be interaction between these two lobes here. And so this is known as our Pi bond, and this is known as our Sigma Bond. And once again, this pi bond will be higher in energy than this Sigma Bond. Another way of drawing this a more simpler way is simply with two bonds here, two dashes here. Now, notice that this is a Sigma bond, and the top one is a Pi bond. |
Alkenes and Double Bonds .txt | And once again, this pi bond will be higher in energy than this Sigma Bond. Another way of drawing this a more simpler way is simply with two bonds here, two dashes here. Now, notice that this is a Sigma bond, and the top one is a Pi bond. So let's review. The Sigma bond contains more S character and is therefore lower in energy and more stable or stronger. Because remember, the more stable something is, the more stronger it is then the Pi bond. |
Alkenes and Double Bonds .txt | So let's review. The Sigma bond contains more S character and is therefore lower in energy and more stable or stronger. Because remember, the more stable something is, the more stronger it is then the Pi bond. Therefore, the Pi bond is less stable because it's higher in energy, and therefore it's more reactive. Now, whenever we input energy to break our Pi bond or to break our double bond, our pi bonds break first. So let's look at one more important detail about our double bonds. |
Alkenes and Double Bonds .txt | Therefore, the Pi bond is less stable because it's higher in energy, and therefore it's more reactive. Now, whenever we input energy to break our Pi bond or to break our double bond, our pi bonds break first. So let's look at one more important detail about our double bonds. So, this is a single bond. This is an ethylene molecule. So notice that in an ethylene molecule, we have one Sigma bond, and the Sigma bond is able to rotate. |
Alkenes and Double Bonds .txt | So, this is a single bond. This is an ethylene molecule. So notice that in an ethylene molecule, we have one Sigma bond, and the Sigma bond is able to rotate. So we create confirmations or confirmations of ethane. So we could have an eclipse confirm, and we could have a staggered confirm. Now, notice what happens in our double bond molecule. |
Alkenes and Double Bonds .txt | So we create confirmations or confirmations of ethane. So we could have an eclipse confirm, and we could have a staggered confirm. Now, notice what happens in our double bond molecule. So here we have the following ethylene lean. So, notice that these ch bonds on Ethylene lean are on the same plane. And these two orbitals here, this Pi orbital is created by an overlap of two P orbitals down perpendicular to either of BCH bonds. |
Alkenes and Double Bonds .txt | So here we have the following ethylene lean. So, notice that these ch bonds on Ethylene lean are on the same plane. And these two orbitals here, this Pi orbital is created by an overlap of two P orbitals down perpendicular to either of BCH bonds. And notice what happens. Notice now there is no rotation. And that's because if there was rotation, these two P orbitals would no longer be in parallel. |
Alkenes and Double Bonds .txt | And notice what happens. Notice now there is no rotation. And that's because if there was rotation, these two P orbitals would no longer be in parallel. When I rotate these, these guys would lose that overlap and therefore would destabilize the molecule. So that means, because these two P orbitals like to stay in parallel to one another, they like to stay in the same plane. This double bond will not allow rotation. |
Kinetic Molecular Theory .txt | And they call these assumptions the kinetic molecular theory. Now, from the math, a Niagara point of view, this isn't really a theory because under real conditions these assumptions don't hold. Yes, these assumptions are important to make because they allow us to come up with concrete conclusions about the behavior of gas molecules. So let's begin. The first assumption is the fact that volume of gas molecules is zero. So where does this assumption come from? |
Kinetic Molecular Theory .txt | So let's begin. The first assumption is the fact that volume of gas molecules is zero. So where does this assumption come from? Well, it comes from the observation that gases are easily compressed and mixed very well. And this is because the distance between the molecules is much larger than the size of the molecules. Now let's look at our inflated ball. |
Kinetic Molecular Theory .txt | Well, it comes from the observation that gases are easily compressed and mixed very well. And this is because the distance between the molecules is much larger than the size of the molecules. Now let's look at our inflated ball. Within our ball, we have lots of different molecules. But the difference between any two molecules is much greater than the size of the molecule itself. And that's why we can compress it because when we compress it, there's lots of space for the molecules to move. |
Kinetic Molecular Theory .txt | Within our ball, we have lots of different molecules. But the difference between any two molecules is much greater than the size of the molecule itself. And that's why we can compress it because when we compress it, there's lots of space for the molecules to move. On the contrary, on solids and liquids the density is much higher and so there is not too much space for them to move. And that's why we can't compress them easily. And that's exactly why when we take this inflated ball, we see that we can easily compress it because there's lots of space for the molecules to move. |
Kinetic Molecular Theory .txt | On the contrary, on solids and liquids the density is much higher and so there is not too much space for them to move. And that's why we can't compress them easily. And that's exactly why when we take this inflated ball, we see that we can easily compress it because there's lots of space for the molecules to move. But if this a ball was filled with solid or liquid, I would not be able to compress it without changing its shape or volume. Let's look at the second assumption. Gases move at high velocities in all different directions. |
Kinetic Molecular Theory .txt | But if this a ball was filled with solid or liquid, I would not be able to compress it without changing its shape or volume. Let's look at the second assumption. Gases move at high velocities in all different directions. So what's the observation or what's the experience from everyday life that tells us that gas is, in fact move at high velocities? Well, for example, if you forgot to wash your feet or you've been wearing your shoes for way too long, you know that if you take off your shoes and there's a girl or a voice sitting across the room, they will definitely smell you instantaneously. That's why you better keep your shoes on. |
Kinetic Molecular Theory .txt | So what's the observation or what's the experience from everyday life that tells us that gas is, in fact move at high velocities? Well, for example, if you forgot to wash your feet or you've been wearing your shoes for way too long, you know that if you take off your shoes and there's a girl or a voice sitting across the room, they will definitely smell you instantaneously. That's why you better keep your shoes on. That's because when you take off your shoes the molecules of air trap in your socks and in your shoes escape and move at very high speeds in all different directions. So the person sitting across the room from you will definitely smell you. So you better keep those shoes on. |
Kinetic Molecular Theory .txt | That's because when you take off your shoes the molecules of air trap in your socks and in your shoes escape and move at very high speeds in all different directions. So the person sitting across the room from you will definitely smell you. So you better keep those shoes on. So the second assumption about high velocities also accounts for the fact that gases will expand into any container quickly and completely. Let's look at our third assumption. So, gas molecules exert no forces on one another due to mass and charge. |
Kinetic Molecular Theory .txt | So the second assumption about high velocities also accounts for the fact that gases will expand into any container quickly and completely. Let's look at our third assumption. So, gas molecules exert no forces on one another due to mass and charge. From everyday experience we know that if we take an object and drop it, it will slide down. Well, why does it slide down? Because the Earth, a much greater mass, pulls the object and this object pulls the Earth as well. |
Kinetic Molecular Theory .txt | From everyday experience we know that if we take an object and drop it, it will slide down. Well, why does it slide down? Because the Earth, a much greater mass, pulls the object and this object pulls the Earth as well. But the Earth is so large, it doesn't really move too much. And in fact, any two objects that have mass will exert a pulling force. Now, the same way charge also exerts a pulling and an attraction force. |
Kinetic Molecular Theory .txt | But the Earth is so large, it doesn't really move too much. And in fact, any two objects that have mass will exert a pulling force. Now, the same way charge also exerts a pulling and an attraction force. Now, all these pulling attraction forces can be neglected in a gas system. Well, this fifth part is not really an assumption. It's more of a conclusion. |
Kinetic Molecular Theory .txt | Now, all these pulling attraction forces can be neglected in a gas system. Well, this fifth part is not really an assumption. It's more of a conclusion. Now, average kinetic energy of molecules is proportional to the temperature. And that simply means if we increase our temperature, we have more kinetic energy. And one observation regarding this assumption is that reactions occur quicker when our temperatures are higher. |
Kinetic Molecular Theory .txt | Now, average kinetic energy of molecules is proportional to the temperature. And that simply means if we increase our temperature, we have more kinetic energy. And one observation regarding this assumption is that reactions occur quicker when our temperatures are higher. And that's because there are more collisions between any molecules. And so these colliding molecules are allowed to react, and so they create products. And that's why our rates are higher. |
Kinetic Molecular Theory .txt | And that's because there are more collisions between any molecules. And so these colliding molecules are allowed to react, and so they create products. And that's why our rates are higher. Now, I want to mention one more thing. Now, recall that kinetic energy is equal to one half mass times velocity squared. So suppose I have two molecules, one heavy molecule and one light molecule with the same kinetic energy. |
Kinetic Molecular Theory .txt | Now, I want to mention one more thing. Now, recall that kinetic energy is equal to one half mass times velocity squared. So suppose I have two molecules, one heavy molecule and one light molecule with the same kinetic energy. Well, according to this formula, if the kinetic energies are the same, then the higher or the heavier molecule will have a lower velocity, while the lighter molecule will have a higher velocity. We could also talk about the average velocities of the molecules, and that's simply average of all the molecules found in our system. So, on average, if you pull out a molecule from our system, it will have an average speed. |
Elements and Isotopes.txt | Now, over 100 different types of atoms exist and each atom is called an element. Now each element found on the periodic table of elements is represented in the following way where this x is the symbol of our atom. Now in this case it's just x. It's a hypothetical symbol. But for example, carbon has the letter C and oxygen has the letter O. Now this A and this C are usually numbers but in this case we're going to use letters. |
Elements and Isotopes.txt | It's a hypothetical symbol. But for example, carbon has the letter C and oxygen has the letter O. Now this A and this C are usually numbers but in this case we're going to use letters. The A is the atomic mass and the Z is the atomic number of our element. Now the atomic mass is the mass of that element. It's the number of protons and the number of neutrons. |
Elements and Isotopes.txt | The A is the atomic mass and the Z is the atomic number of our element. Now the atomic mass is the mass of that element. It's the number of protons and the number of neutrons. Now note that electrons are not counted Naratomic mass because their mass is much smaller than that the proton or the neutron. Now the atomic number is the number of protons of our element. Now that number, the atomic number is the identity number of that element. |
Elements and Isotopes.txt | Now note that electrons are not counted Naratomic mass because their mass is much smaller than that the proton or the neutron. Now the atomic number is the number of protons of our element. Now that number, the atomic number is the identity number of that element. It's used to identify our element. It's the fingerprint of that element. And that's because any element can have different number of electrons or neutrons but it will always have the same number of protons. |
Elements and Isotopes.txt | It's used to identify our element. It's the fingerprint of that element. And that's because any element can have different number of electrons or neutrons but it will always have the same number of protons. And that's why you could use the atomic number to identify our x, our element. The second that the number of protons changes that means our element also changes. Now let's go into something called isotopes of elements. |
Elements and Isotopes.txt | And that's why you could use the atomic number to identify our x, our element. The second that the number of protons changes that means our element also changes. Now let's go into something called isotopes of elements. Now, two or more atoms that contain the same number of protons mean they're the same elements but have different number of neutrons, are called isotopes of that same. Let's look at a very common example of carbon. Now carbon has three isotopes. |
Elements and Isotopes.txt | Now, two or more atoms that contain the same number of protons mean they're the same elements but have different number of neutrons, are called isotopes of that same. Let's look at a very common example of carbon. Now carbon has three isotopes. Now in each case because this is a carbon atom it must have the same number of Z. The atomic number must be the same. In other words, all three have six protons. |