expt 4 - spectrophotometry - M A PUA I NST I T U T E OF T...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
MAPUA INSTITUTE OF TECHNOLOGY School of Chemical Engineering, Chemistry, Biological Engineering, and Material Science and Engineering Physical Chemistry Laboratory 2 - 3 rd Quarter SY 2010-2011 Neil Patrick P. Tangara , 3 rd Year B.S. Chemical Engineering Experiment No. 4 SPECTROPHOTOMETRY Meynard Austria 1 , Neil Patrick Tangara, Darlene Pudolin, Emily Rose Santos, Aeiocellis Tan, Creza Loraine Talingting 2 1 Professor; 2 Students, all from CHM171L/A31, School of Chemical Engineering, Chemistry, Biological Engineering & Material Science and Engineering, Mapua Institute of Technology ABSTRACT This experiment intends to utilize spectrophotometry to determine the visible light range based on wavelengths for the human eye and the effect of concentration on absorbance in a solution and to determine the unknown concentration of a sample using Beer’s plot. It was found that the human eye has a visible light range of approx. 400-650 nm. Also, concentration was found to vary directly with absorbance and inversely with transmittance. The unknown concentration was interpolated to be 0.00709 M using the best-fit-line equation generated by plotting concentration versus absorbance. This report will discuss why such a phenomenon occurs. Keywords : spectrophotometry, wavelength, absorbance, Beer’s plot, transmittance INTRODUCTION A spectrophotometer is employed to measure the amount of light that a sample absorbs. The instrument operates by passing a beam of light through a sample and measuring the intensity of light reaching a detector. When a photon encounters an analyte molecule (the analyte is the molecule being studied), there is a chance the analyte will absorb the photon. This absorption reduces the number of photons in the beam of light, thereby reducing the intensity of the light beam. One of the most common applications of spectrophotometry is to determine the concentration of an analyte in a solution. The experimental approach exploits Beer's Law, which predicts a linear relationship between the absorbance of the solution and the concentration of the analyte (assuming all other experimental parameters do not vary).
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern