00:01
For number 14, we're to find the binding energy per nucleon for each of these elements.
00:07
Let's remember what that is.
00:09
You can find the mass defect, how much mass is missing by adding up the mass of the individual pieces.
00:18
So the mass of all the protons plus the mass of all the neutrons.
00:26
Those together are always a little bit more than the mass of the overall atom combined.
00:32
So i'm calling that mass total.
00:37
And that's something you can look up in appendix b in the back of the book.
00:43
So that missing mass is the binding energy.
00:46
So we'll calculate that mass in u's atomic mass units and then convert it to energy.
00:54
So here, i read my equation all set up here.
00:57
This is the mass of a proton in use.
00:59
This is the mass of one neutron in use.
01:02
So we're given iron 56.
01:05
So i can tell on a periodic table that the atomic number is 26.
01:10
So that means it has 26 protons.
01:15
And mass number remembers the sum of protons and neutrons.
01:19
So i subtract and i get that it has 30 neutrons.
01:23
And then i looked up on the table, iron 56, and that is 55 .934.
01:40
I do that math and i get that there is a mass defect of 0 .5 to 846 and that is measured in u atomic mass unit.
02:04
I'm gonna convert that.
02:06
I'm gonna convert that to the energy equivalent i know that 1 u is the same as 931 .5 mega electron volts so my u cancels.
02:29
So my binding energy is 492 .26 mega electron volts...