 Okay, so let's do our last problem of the day. It's another one of these binding energy problems. So you guys should be able to Do these problems on your own now, but let's just go through one more. I got thank you there So this one says the atomic mass of iodine 127 is 126.9004 AME Calculate the nuclear binding energy of this nucleus the corresponding nuclear binding energy per nucleon and Nuclear binding energy per mole of the high 127 nucleus, okay So just to remind you and again, this is a process and I'd like to go through the same process every time Okay, what equation are we using? thynestein equation, right? So does everybody remember that equation? So C remembers the speed of light that's given to you But delta M we have to figure out, right? So M the mass of 127 I I 127 is given to us But the difference in mass is going to be well, it's going to be this Minus the total number of nucleons mass, okay, so how do we figure that out? So the mass of the total number of nucleons So what do we have to do? to do that number of protons and the number of Neutrons, right? So how many protons does I 127 have it? 53, right every iodine atom has 53 protons or would be an iodine So we say 53 times 1.007 825 AMU And remember eventually we're going to change these AMUs to kilograms. Okay, so how many? Neutrons does the I 127 have it? 74 and how do we get that? 127 minus 53 Equals 74 Okay, so let's add that up. I got a number Very close to 126.9 as you would expect 128.0 5 5 6 1 9 5 AMU Okay, so the Delta mass the difference in mass between the Projected nuclei and the actual nuclei is going to be well remember what we do we do the mass of the Nucleus we're interested in minus the mass of the total nucleons. Okay, so mass 127 I minus mass of the total nucleons, okay so we're going to have 126.9004 AMU minus 128.0 5 5 195 AMU Yeah, so it took 4 after the decimal negative 1.15 4 8 AMU Okay But remember Remember, what did we say energy here is going to be in joules one joule equals? one kilogram meter squared Second squared so what does that mean? Well, we're going to when we plug this into this equation will have meter squared second squared But we have AMU for our mass units now, so we want to switch that to kilograms. Okay so in order to do that you're going to have to Well use this Conversion factor 1 AMU equals 1.661 times 10 to the negative 24 Grams, okay, that'll be given to you. So I'm just going to switch to kilograms right now so 1.661 times 10 to the negative 24th grams one kilogram divided by 1,000 So when I do that AMU cancel grams cancel and we're left with kilograms Okay, so let's do that together Okay, so the difference in mass between these two Numbers is going to be negative 1.918 Times 10 to the negative 27 Okay So now so does everybody follow me to this point Okay So I'm going to erase this top part up here so we can in fact why don't I just put the delta ham over here We'll erase the whole thing So negative 1.918 times 10 to the negative 27 Okay, so change in energy c squared so negative 1.918 Times 10 to the negative 27 kilogram 3.00 Times 10 to the 8 meters per second squared So remember this is the energy that's being released that we're about to get Hopefully you see it's going to be a negative number. Okay, the binding energy itself is a positive number It's going to be the opposite of this number that we're getting. Okay Okay, so So I get so this is also we got to remember this is per Iodine 127 Okay, so that's per atom that we're doing Okay, so for the energy release per 127 iodine atom is going to be Negative 1.7 to 6 times 10 to the negative 10 joules Curve. So what's the binding energy? It's going to be what? 1.7 to 6 right to the negative 10 joules per I-27 Okay, what's the binding energy per nucleon now? So What's the number of nucleons in this? Adam how many nucleons Tell me don't point to it 127 It's not hard So the binding energy per nucleon is going to be 1.7 to 6 times 10 to the negative 10th joules per one I-27 atom But we know for every one I-27 We have 127 Nucleons, so we okay with doing that. So we're going to divide this by one 27 1.3 by Times 10 to the negative 12 Joules per nucleon. So that's the binding energy per nucleon So I'm going to erase This part here, I'm going to leave this because we're going to need that I'm going to erase that top part of there though Is now we're going to find the binding energy per one mole of these atoms Okay, and remember oftentimes you want to put this in kilojoules Because the number is going to be big. Okay, so That's the binding energy per atom so the binding energy per a mole of I-1 127 is going to be what? 1.7 to 6 times 10 to the negative 10 joules per one 127 I But what do we know? for every One mole we have 6.022 times 10 to the 23rd atoms So in this case for every one mole I-27 atoms We have 6.022 times 10 to the 23rd 127 cancel cancel like that But what do we say we also want this in kilojoules, so Okay, so take that 1.2 1.7 to 6 Times 10 to the negative 10th multiplied by 6.0 22 23 and then divide that by a thousand and Two or six bigs you get 1.0 four zero Times 10 to the 11 kilojoules per mole that's the binding energy of I-1 Any questions on that one? Okay, so now you have a couple of problems that you can go and watch okay Make sure you know how to do these then it by the next time we see each other, okay? Okay, we kill it