![]() There are two types of reasons for nonlinearity, chemical and instrumental. The default is Absorbance versus Wavelength. ![]() Check the USB cable connections this is the most common problem. If not, communication between the program and spectrometer has failed. The rule of thumb that we will use in this lab applies only to the spectrometers we use, and that is that we can only trust values between A= 0.05 and A=1.0. Emission Spectrometer Set-Up Connect the spectrometer USB cable to your laptop. The extinction coefficient is often a very large number which allows one to measure very small concentrations of solute, and it is a property of the molecule, but is influenced by the solvent.īeer's Law is linear over a small range of absorbances and you can not believe all readings a spectrometer gives you. If status line displays the message No device connected, as it does in Fig. 5)Fill in each cell in the XXXX Error column with the uncertainty of the data point in the same row. 4) Choose the Use Column radio button, select XXXX Error, and click Done. ![]() Much of the material has been extensively tested with science undergraduates at a variety of levels at the University of Toronto. Our line passes through all the uncertainties it fits 3) Follow Steps 1 3 in the Constant Error section. Where A is the unitless absorbance, I o is the intensity of light entering the sample, I t is the intensity of light transmitted out of the sample, b is the path length, c is the concentration of the molecule absorbing the light and \(\epsilon\) is the extinction coefficient and has the units of concentration -1 length -1. Chapter 3 Experimental Errors and Error Analysis This chapter is largely a tutorial on handling experimental errors of measurement. So after converting to log base 10 (which is done for historical reasons) we get ![]()
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