00:02
Okay, so for this problem, we are given what the wavelength is at different values of n.
00:09
And we're going to calculate what the energy is in kilojoules per mole.
00:14
One thing to note before we start is that because all those wavelengths are given in nanometers, when we use them in our equation, we are going to multiply them by 10 to the negative 9th in order to get them in terms of meters, not nanometers.
00:28
So for each problem, we're going to use the same equation of e is equal to hc over lambda, where h is our constant of 6 .626 times 10 to the negative 34.
00:45
C is our constant of 3 times 10 to the 8th.
00:48
And then our wavelength, we'll start with the first one when n is 3.
00:53
Our wavelength there is 656 .3 times 10 to the negative 9 meters.
01:01
And then we want our energy in terms of kilojoules per mole.
01:05
So in order to get into kilojoules, we will need to divide by 1 ,000.
01:10
And in order to get per mole, we're going to multiply by 6 .626 times 10 to the negative.
01:19
Sorry, wrong problem.
01:21
Our avagosha number of 6 .022 times 10 to the 23rd.
01:30
So when we multiply all that out, we get an answer of 182 .3 kilojoules per mole...