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University of Central Florida
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00:55
Eugene S.
What is heat? Explain the difference between heat and temperature.
02:00
Wilson M.
Explain the difference between a pure covalent bond, a polar covalent bond, and an ionic bond.
04:56
Shahriar K.
What is a buffer? How does a buffer work? How does it neutralize added acid? Added base?
03:15
Keenan M.
What is the magnitude of the dipole moment formed by separating a proton and an electron by 100 pm? 200 pm?
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And so, for our next problem will be looking at the different big Gap structures for the following knowledge. In answering a couple of questions related to and so for the first one will figure out which material is the most active and which one is the least connected. So let's recall that for our backup structures we have a conducting band which are essentially the limos or, in other words, fellows, unoccupied Molecular Orbital's for a given material. And we also have the balance pan, which is essentially the Homo or the highest occupied in molecule orbital. And so these are where the Beyonce electrons will be, and so we can see that if we compare, be solid a BNC. We can see that for the most part there is some kind of connection band and some kind of valence band. But the more important thing to note is the band gap. And so the space in between the conduction man and even Span is the band gap, and so the band Gap will actually dictate how productive these materials are. And so if we have larger bank gaps like that scene and be, we can see that a lot of energy is required to excite the electrons into the connection band. If we look at the case of B, ah of A and C, we see that for the most part, the bank caps are also not very large. And so if we have smaller bank caps, that means that less energy is regard to excite the electrons into the collective band. And so that means that these materials are more connected. And so the first part, we can say bath material that is most collective is the solid A. Just because for solid a VPN Gap is the smallest of three solids on DSO, it requires the scent of energy. Thio Get the electrons excited into the connecting band, which will then allow it to move around the structure. And as for the solid, that is least connective. We would have to assign be just because it has the largest band gap out of all of the materials. And so a lot of energy is required to excite the electrons into the conduction band, and because of that, it is more probable for the electrons to stay in de Valence band. And so there are no electrons that can be. And as for your second part, we need to figure out a way to decrease the conductivity of seats. And so what a way to increase or decrease the conductivity is actually induce introducing impurities. And so, for this case, if we want to decrease the connectivity, we need to make this a P type semiconductor. And so we would add some kind of impurity such that we can create holes in the Valence band. And to do this, we would actually need some kind of accept your band. And so what happens is that if we have next after band and we have electrons, that can be excited. Um, but not excited to the connection band you can actually fill up. This is contraband. And so if we fill these with electrons, we know that the electrons are now residing in the etcetera band and not in the Valence Band. And so what happens is that we leave these holes behind, and so because we are preventing the electrons from entering the connection band by introducing the sex after band were actually decreasing the connectivity of solid C, and so that would be one way to decrease the connectivity. And if we think about the opposite And so in this case, we want to figure out if we can increase the connectivity, we would actually make an end type semiconductor or introduce and impurity that can actually donate electrons into the conduction band of the material. And so if you have a donor band special here, we know that from the dinner band we have a bunch of electrons occupying the span. And so the, um, relative band gap between the donor banned any contraband is actually quite small. And so it's easy for the electrons to be excited into the conduction band. And so if we make this process easier, that means that we're increasing the conductivity of the material because we're basically closing the gap between the electrons that can be excited into the meanwhile of these islands. And so that is one way to increase the connectivity of carbon and off. Just thio reiterate this point. And so in this case, we're actually making a lower Lucio that is living. And so because of this, we have a way to excite the electrons without going always the congressman, the connection band or as for the, um, impurities that act as the donors thes will actually become a higher Homo band or where the valence electrons are too excited into the convent. And so, by looking at the different bank AB structures, we can actually predict the conductivity of the materials based on how large the band gap is.
Solutions
Kinetics
Chemical Equilibrium
Acids and Bases
10:01