Investigating The Effect Of Acid Base Indicator On The Concentration Of A Said Substance Essay

1128 Words5 Pages
Introduction In analytical chemistry, there are numerous methods that can be utilized in order to analyze different substances by determining the composition or concentration of a said substance, which is the main goal (Analytical Chemistry, n.d.). One of those methods available, and used widely in analytical chemistry, is spectroscopy. Spectroscopy utilizes the quantification of light; which is based upon intensity, amount absorbed, and amount transmitted, in order to determine the concentration of a given substance (Vo, 2016). For the following lab, the main goal is to determine the pKa of an acid-base indicator by means of spectroscopy. There are numerous types of spectrometers that can be utilized for the purpose of this lab; the one utilized for this lab is the Spec20D. An acid-base indicator is a substance that is added to s solution and indicates pH change by means of changing colors. For example, bromocresol green is an acid-base indicator, which is a monoprotic organic acid with a molecular weight of 698.02 g/mol. The absorbance of the indicator solution will be tested over a range of wavelengths utilizing the protonated form to determine the wavelength of highest absorbance; then the same tests will be conducted, but when the indicator is in the deprotonated form. Lastly, the tests will be conducted with both species present, utilizing the wavelengths derived from the first two tests. The data will then be plotted and the pKa can then be derived. For the
Open Document