An Introduction to Spectrometric Methods

Define analysis

• Detailed examination of elements or structure of something

• Detailed examination of something without purpose

• Examination of a structure of something

• Examination of physical structures of elements

Choose the CORRECT definition of quantitative analysis

• Measurement of the quantities of particular constituents present in a substance

• Measuring the physical appearance of substance

• Measuring the weight of a particular constituents present in a substance

The following are examples of instrumental methods, EXCEPT

• Conductivity

• Chromatography

• Spectroscopy

• Gravymetry

Choose the wrong example of chromatography

• High Performace Liquid Chromatography (HPLC)

• Gas Chromatography (GC)

• Thin Layer Chromatography (TLC)

• Rudimentary Analysis (Run DMC)

a) A spectrophotometer measures radiation transmitted through samples. A sample of an analyte with a concentration of 5.64 x 10⁴ M produces a transmittance of 63.9 % in a 3.80 cm cell. Calculate the transmittance of the solution in a 1.00 cm cell.

• 0.889

• 0.194

• 0.639

• 0.050

Classify the characteristic properties of the following spectrometers as absorption, emission or scattering.

i) Fluorescence spectrometer

ii) Fourier transform infrared spectrometer

iii) Raman spectrometer

iv) Ultraviolet-visible spectrometer

Chloroaniline (Mw= 127.6 gmol^-1) in a sample is determined as the amine picrate, which absorbs strongly at 359 nm (ε= 1.25 × 104 cm-1.L.mol-1). A 0.0265 g sample of chloroaniline is reacted with picric acid and diluted to 1 L. The solution exhibits an absorbance of 0.368 in a 1.00 cm cuvette. Calculate the weight of chloroaniline in the sample.

• 3.75 x 10^-3 g

• 2.94 x 10^-5 g

• 1.2 x 10⁴ g

• 9.5 x 10⁴ g