## rydberg's constant

$c=\lambda v$

Agustina Santa Cruz 2F
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### rydberg's constant

On the equation sheet, rydberg's constant is 3.28984 x10^15 Hz, but online, it's usually 1.097x10^7 m. Which one is better to use and why do they differ?

Brianne Conway 1D
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### Re: rydberg's constant

"The value of the Rydberg constant R∞ is 1.0973731568508 × 10^7 per metre. When used in this form in the mathematical description of series of spectral lines, the result is the number of waves per unit length, or the wave numbers. Multiplication by the speed of light yields the frequencies of the spectral lines." This is the description given by Encyclopedia Brittanica, and when you multiply the 1.097 x 10^7 m value by the speed of light it gives the 3.28984 x 10^15 Hz value. Basically it's the same value, just in different units.

Yuelai Feng 3E
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### Re: rydberg's constant

Hi! In terms of solving homework problems I have only used '3.28984 x10^15 Hz' so far. Perhaps the other value is more useful when solving other types of questions which we have not yet encounter. :)

Sami Siddiqui 1J
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### Re: rydberg's constant

For all the homework and additional practice questions I've done, I used 3.29e15 as Rydberg's constant and it worked like a charm.

Courtney Situ 2B
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### Re: rydberg's constant

Hello!
I also just wanted to add on a little bit to everyone's answers. The R = 3.28984 x10^15 Hz is used for the Rydberg equation with frequency, or v = R(1/n1^2 - 1/n2^2).
In comparison, the R = 1.097x10^7 m is used for the Rydberg equation with wavelength, or 1/wavelength = R(1/n1^2 - 1/n2^2). As the previous answers state, the conversion between wavelength and frequency accounts for the differences in the two Rydberg constants. The answer should be the same no matter which formula and constant you choose, but be careful and make sure you match the correct Rydberg constant to the correct formula.
As for which formula you should use, it's really up to you.
Hope this helps!

Mackenzie Van Val 3E
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### Re: rydberg's constant

Hi! The 3.29e15 Hz is the version of the Rydberg constant that is on Dr. Lavelle's Constants and Equations sheet, so I'd say that at least for now, that is definitely the more convenient/recommended version of the constant to use for this class. It is also the constant that I assume works with the version of the Rydberg equation listed on the Constants and Equations sheet. Also, during Justin's UA Workshop on Saturday, he said that you should only expect to use the 3.29e15 Hz Rydberg constant on the midterm, so I'd definitely say that's the better option to use. I hope this helps!

Emma Ide 2E
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### Re: rydberg's constant

3.289x10^15 is the only value that we will need to use for the midterm. This is in Hz or s^-1, which works for all the calculations we are doing right now.

Rachel Jiang 3H
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### Re: rydberg's constant

Hi! Since the Rydberg's constant is R= 3.28984 × 10^15 Hz or s^-1 on the equation and constant sheet that Dr. Lavelle provided us with, using this number would probably be better.

Moura Girgis 1F
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### Re: rydberg's constant

The the several practice problems we have done for this class so far, the value for the Rydberg constant was 3.289x10^15, so that should be the only value you use when solving the problems as far as Chem14A goes.

Gian Boco 2G
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### Re: rydberg's constant

It depends on which equation you plug it into because like they said, same value but different units and the relation is based on the light energy equaiton.

Anastasia Yulo 1C
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Joined: Wed Sep 30, 2020 9:47 pm

### Re: rydberg's constant

It depends on which equation is being used.

R = 3.28984 x10^15 Hz is used for the Rydberg equation with frequency, or v = R(1/n1^2 - 1/n2^2).
R = 1.097x10^7 m is used for the Rydberg equation with wavelength, or 1/wavelength = R(1/n1^2 - 1/n2^2).

205323697
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### Re: rydberg's constant

Just to clarify, this only works with hydrogen or other atoms that have the same amount of electrons as Hydrogen, correct?