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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: kaukeo on October 04, 2006, 08:25:15 PM

Title: wavelength and frequency
Post by: kaukeo on October 04, 2006, 08:25:15 PM

I'm really lost about the formulas for this unit.

1. Water has a strong infrared absorbance at 1500 cm^-1. What is the wavelength of this frequency?

I tried frequency = (3.00*10⁸) / 15^-1 (after i converted to m).

But my answer isn't on my answer key. Can someone tell me what I'm doing wrong?

Title: Re: wavelength and frequency
Post by: mike on October 04, 2006, 09:06:06 PM

I thought 1500cm^-1 is a wavenumber so the wavelength is just the inverse of this. In other words this is the wavelength (or inverse wavelength, and not frequency).

So wavelength is 1/1500 = 6.66x10^-4cm