5. In a tabular form, present the different wavelengths of light in the visible region of the spectrum, the colors of a solution observed, and the color or light absorbed by the solution.

The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range ofwavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 700   nm .

Color observed Wavelength Color absorbed WavelengthMagentaVioletBlue violetBlueCyanGreenYellow greenYellowYellow orange

400417435477477500556625667

Orange Red orangeRedGreen yellowYellowYellow orangeOrangeRed orangeRed

667715770556625667667715770

Source: http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/Spectrpy/UV-vis/spectrum.html

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/specol.html

6. What are the different types of blank solution?

A. Equipment Blank- a sample of analyte free water poured over a decontaminated field sampling equipment prior to the collection of environmental samples. The purpose of this blank solution is to assess contamination from the total sampling, sample preparation and measurement process, when decontaminated sampling equipment is used to collect samples. The results include total field and laboratory sources of contamination.

B. Field Blank- a sample of analyte free water poured into the container in the field, preserved and shipped to the laboratory with field samples. The purpose of field blank is to assess contamination from field conditions during sampling. The results include total ambient conditions during sampling and laboratory sources of contamination.

C. Trip Blank- A clean sample of a matrix that is taken from the laboratory to the sampling site and transported back to the laboratory without having been exposed to sampling procedures. Typically, analyzed only for volatile compounds. The purpose of this blank solution is to assess contamination introduced during shipping and field handling procedures. The results include shipping and laboratory sources of contamination. Volatiles only.

D. Method Blank- A blank prepared to represent the matrix as closely as possible. The method blank is prepared/extracted/digested and analyzed exactly like the field samples. The purpose of this blank solution is to assess contamination introduced during sample preparation activities. The results show only laboratory sources of contamination.

E. Instrument Blank- A blank analyzed with field samples. The purpose of this is to assess the presence or absence of instrument contamination. The results show only laboratory sources of contamination.

http://www.epa.gov/region3/esc/qa/pdf/blanks.pdf