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[BLANK_AUDIO].

Hi there.

So, this is just a quick run through on the treatment of the data

you've obtained for the hydrogen emission simulator.

So, if you, on page three of the, the,

the descriptor you'll find the, the title data treatment.

Now the first thing we're supposed to use is, well first use its, the

simulator, and you obtain the wavelengths in

nanometers of four lines in the Balmer series.

So these were obtained on the simulator by you, you, you, taught it how to do that.

And, and, and the simulator program.

And, you position the cross hairs as best you can.

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And then, the first thing you have to do is convert these to electron volts.

So, a good way to treat the data, again as we mentioned

lower down on the descriptor, is to put the data into a spreadsheet.

So, here are the four lines.

Using the same list that I measured.

1:12

So you, four, four nanometer values.

And then the first thing I asked you to do was convert these to electron volts.

And this is just simply a, a simple conversion factor.

There's loads of these on the Iinternet.

The one I use is given here.

So this, all you have to do is simply type in the values in nanometers that you get

from the simulator, and it will give you the electron volt's values.

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So if we go back to the, descriptor again, so

the next step then, was you had to identify the transitions.

And then you had to use a little bit of what we found out in the lecture.

You know, the lower energy has a principal quantum number, n equals 2.

because the Balmer series corresponds to n equals 2.

So therefore, you know the lines

must correspond to transitions from higher levels.

So, basically, you've observed tje first, four lines.

So the transitions are from three to two, four to two, five to two, and six to two.

And then you were given how to assign them so

which transition in the Balmer series is lowest energy change.

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Which of the observed lines corresponds to the lowest energy.

And which is the next lowest transition and

which line corresponds to the next lowest energy.

So again, if you look back on the lectures, you know that the,

the lowest energy, the lower energy gap corresponds at three to two level.

Then you go.

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I've done this in the spreadsheet here.

So here we have the highest wavelength band.

The highest wavelength corresponds to the lowest energy.

So, that's from the three-to-two transition so

N2 in this case is going to be three.

Next one, N2's going to be four.

Next one's going to be five.

And the next one is going to be, is going to be, to be six.

[NOISE] So going back then to the description again.

Next thing you're asked is to plot a graph

of the energy of each transition in electron volts.

But I've already calculated the transition energy of electron volts.

And then you have to work out 1 over N2 squared.

So using Excel or a spreadsheet.

And your oh, asked to obtain the gradient.

And the, and the intercept.

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So first let's show that on Excel.

So here we see we, in addition to the, the

energy is in nanometers, the energy is in electron volts here.

We have the N2 values.

Then we did the N2 squared values.

And now we have one over N2 squared because that's what we were asked to plot.

So we were asked to plot one over N2 squared against electron volts.

And using the plotting routine in, Excel, you

obtain the graph given here where you have the

energy electron volts on the Y axis and one over N2 squared on the, on the X axis.

And here you have your straight line.

And then you have the equation for the straight line.

Y is equal to this equation for a straight line.

It's y is equal to m x plus c.

And the next step then was to use this plot to obtain the, the Rydberg constant.

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So going back then to our, our descriptor again.

So we've just finished here plotted a

energy electron volts versus one over n squared.

And we have the gradient and we have the intercept.

Now it says to adapt equation six and express in the form of y equals m x +

c and use it to evaluate the Rydberg constant,

r, separately from both your calculated gradient and your intercept.

So let's first go up to equation six here.

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So here you have delta-e.

So we can say that's equal to, we're just going to multiply out by R.

So it's R over n1-squared

minus R over n2 squared.

So what I'm going to do now is slightly rearrange that to make it clearer for you.

I'm just going to set this equal to minus R into

1 over n2 squared plus R over n1 squared.

Now n1 from the Balmer series is going to be two, so

n1 squared, two squared, is going to be, it's going to be four.

And this is your classic y is equal to m x plus c plot.

So this is delta-e is to y.

And here you have m x.

M is going to be minus r and x is, so

what we're plotting on the x axis is one over n2 squared.

Plus c, our intercept is going to be r over four.

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So if we plotted that, what you'd get, say here is a rough sketch.

So here you have your y, which is going to be a delta-e in electron volts.

Here you are going to have one over n2 squared.

And you have four points, so your four points are that.

You draw a straight line through them.

Your slope then, is going to be, minus R, with a negative after Rydberg, constant.

And your intercept here, is going to be the Rydberg constant divided by 4.

So now if we move back here to our plot.

[SOUND] We can see we've plotted this already.

So now we know that the the negative of the

slope is the Rydberg constant, and it's in electron volts.

So it's -13.588 or -13.6 electron volts, which is the value, of course.

You know everybody from, from the lectures, and also the slope is, 3, 3.4,

which is equal to of course the Rydberg constant, R, divided by, divided by 4.

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And so the last thing then, so is this just two points down here.

We've done this.

We've shown how to adapt the equation six.

And you've estimated R from the gradient and the intercept.

And then, you used the value of R to estimate the ionization energy.

Of course you know that the ionization energy

is the, is the energy required to remove the

electron, completely from the ground state, so that's

going to be just simply, the value of R.

So the ionization energy for say, for the hydrogen atom is 70.6 electron voles.

And then what would those do is convert that into other, another values.

Energy in kilojoules per mole, or centimeters minus one.

And here you're given the conversion factors.

So for the estimate the ionization of hydrogen,

you'd just multiply 13.6 by this value here.

96.487 kilojoules per mole.

You want it in cm minus 1 [SOUND].

You can multiply it by 8065.6 cm minus one, and then you should be

able to compare your result to values that you find in the, in the lecture.

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