CHEM 2036: Chemistry for Chemical Engineering & Metallurgy - Spectroscopy Flashcards

Flashcards covering key concepts in spectroscopy for CHEM 2036, focusing on principles, applications, and instrumentation.

Name three types of spectroscopy used for elemental analysis.

Atomic Absorption Spectroscopy, Inductively Coupled Plasma Atomic Emission Spectroscopy, X-ray Fluorescence Spectroscopy

What happens when electromagnetic radiation interacts with matter in spectroscopy?

The interaction of electromagnetic radiation with matter can cause scattering and/or transitions between the energy levels of the matter.

What is the relationship between transmittance and absorbance?

Transmittance decreases as the absorbance of the solution increases.

State the Beer-Lambert Law.

A = εbc (Absorbance = molar absorptivity * path length * concentration)

Why is it important to measure absorbance at λmax?

Maximum sensitivity, allowing for lower concentrations to be reliably measured.

Briefly describe the atomic spectroscopy process.

Atomic spectroscopy involves atomizing a sample at high temperatures to obtain atomic spectra in the UV and visible regions.

Name two potential interferences in Atomic Absorption Spectroscopy

Spectral and chemical interferences.

What is used to produce atoms and ions in Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES)?

A plasma is used to produce atoms and ions.

What reduces some chemical interferences in ICP?

High temperatures.

What type of electromagnetic radiation is used in X-ray Fluorescence (XRF)?

X-rays

List some applications of X-ray Fluorescence (XRF).

Rapid elemental composition of materials, quality control in manufacturing, and analysis of geological materials.

What are the basic differences between atomic emission and atomic absorption?

Atomic emission measures emitted light, while atomic absorption measures absorbed light.

Explain the importance of the hollow cathode lamp in Atomic Absorption Spectroscopy (AAS).

The hollow cathode lamp emits the specific wavelength of light that the analyte atoms absorb.

Explain the function of a monochromator in analytical spectroscopy.

A monochromator selects a specific wavelength of light to be measured.

Explain why chemical interferences are less common in ICP-OES than in flame AAS.

The high temperatures of the plasma reduce chemical interferences.