Ex1 uv-vis spec 20

Wed, 06/05/2013 - 08:23 -- sewm02

Ex1 uv-vis spec 20

Question 1: Diagram a dual beam UV-Vis spectrometerand identify each part of the spectrometer

Reference (Michelle)

http://www.chemistry.adelaide.edu.au/external/soc-rel/content/dualbeam.htm

Annotation

This is a site by the Department of Chemistry at the University of Adelaide in Australia (trustworthy site). The site was accessed 1-26-08. It shows the schematic of a dual beam UV-Vis spectrometer.

Reference (Michelle)

Quantitative Chemical Analysis Textbook (7th ed.)pp.424-449

Annotation

This is from our Analytical/Instrumental textbook. These pages talk about the parts of the spectrophotometers. There is also a good schematic on page 425.

 

Question 1: A. Diagram a monochromator (wavelength selector) that uses a grating.

Reference (Jana)

Annotation

This site does not contain lots of information, however it does have a nice picture of a monochromator that uses grating. There is also some useful information in the short paragraph. Accessed: 1/26/08

Question 1: B. Diagram a monochromator (wavelentgh selector) that uses a prism.

Reference (Jana)

Principles of Instrumental Analysis, 5th edition pages 158-159

Annoation

This is one of the books on reserve in the library. It has descriptions of a prism monochromator principlals of instrumental analysis. It also has a couple of figures that could be used to help visualize.

 

Question 1: C. What optical materials are used for UV-Vis spectoscopy and over what spectral region are they transparent?

Reference (♥Joanna♥)

Fundamentals of Analytical Chemistry, 8th edition pages 745-746

Annoation

This is taken from Scanlon's book on reserve in the library. It identifies the specific optic materials and includes a useful chart with wavelengths. ;]

 

Question 1: D. Describe how a phototube works.

Reference (Jana)

Principles of Instrumental Analysis, 5th edition pages 169-170

Annoation

This is one of the books on reserve in the library. It describes the workings of a phototube and also shows a diagram.

 

Question 1: E. What type of sources are commonly used?

Reference (Michelle)

Quantitative Chemical Analysis Textbook (7th ed.)pp.426-428

Annotation

These pages list the different sources of light used in spectrophotometers and explains how they work.

 

Question 1: F. What is the effect of a chopper.

Reference (Jana)

Quantitative Chemical Analysis Textbook, 7th editon pages 425, 449

Annotation

There is a breif paragraph that descripes the chopper and what it does. The chopper is also shown in the diagram on page 425.

 

Quesion 2: Give an example diagram of a molecule, as in the book, that describes the process that occurs during the absorption of a photon. Be sure to indicat all possible absorption processes.

Reference (Jana)

Quantitative Chemical Analysis Textbook, 7th editon page 390

Annotation

This page shows the energy diagram and in the reading describes the process that occurs.

 

Question 3: Deviations of Beer's Law

Reference (Michelle)

http://www.ic.sunysb.edu/class/che133/lectures/beerslaw.html

Annotation

This site is from the Department of Chemistry at Stony Brook University (trustworthy site). It tells about three phenomena that can cause deviation to Beer's Law and explains how they affect it. Accessed 1-26-08.

Reference (Michelle)

Principles of Instrumental Analysis (5th ed.) pages 303-306

Annotation

This is one of the books on reserve in the library. The pages referenced list limitations and deviations to Beer's Law along with an explaination of how each one affects the curve of the graph.

 

Question 4: Explain the solvent effects that cause a blue shift and a red shift. Why do they call them a red shift and blue shift.

Reference (Michelle)

Undergraduate Instrumental Analysis, 5th Edition pages 268-271

Annotation

This is one of the books on reserve in the library. There is a bit more detail in this book than in our Instrumental/Analytical book. There are also a few figures to look at.

 

Question 5: Calculate energy, frequency and wavenumber of light with a wavelength of 537nm.

Reference (Michelle)

Quantitative Chemical Analysis Textbook (7th ed.)pp. 379-381

Annotation

This is from our Analytical/Instrumental textbook. These pages give the equations needed to do the required calculations. The book also explains what all variables in the equations represent, the constants needed for the equations and an example problem is worked out on page 380.

 

Question 6: What physical processes take place duing the absorption of uv and visible light by a molecule.

Referece (Jana)

Quantitative Chemical Analysis Textbook, 7th editon pages 387-391

Annotation

The book gives different processes that occure during the absorption of a light molecule. You have to read through all of the material to get all the processes and explainations.

 

Question 7: Why does a red solution look red?

Reference (Michelle)

http://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/UV-Vis/spectrum.htm

Annotation

This site is from the Department of Chemistry at the University of Michigan (trustworthy site). It gives an explaination of of how the color wheel works and what color something will appear when it absorbs light at specific frequencies. I accessed this site on 1-26-08.

 

Question 8: Diagram a spec-20.

Reference (Jana)

http://www.uwplatt.edu/chemep/chem/chemscape/LABDOCS/CATOFP/measurea/concentr/spec20/page.htm#description

Annotation

This site is from the University of Wisconsin. It shows diagrams and detailed descriptions of the spec-20. Accessed: 1/26/08