Spectroscopic, Diffraction and Microscopic Techniques

Flashcards covering key concepts in spectroscopy, diffraction, and microscopy techniques.

What is Beer-Lambert's Law?

Beer-Lambert's Law states that the absorbance of light by a substance in a solution is directly proportional to the concentration of that substance and the path length of the light through the solution.

What are the components of Beer-Lambert's Law?

Beer-Lambert's Law is expressed as A = εlc, where A is absorbance, ε is the molar absorptivity, l is the path length of the light, and c is the concentration of the solution.

What does the term 'molar absorptivity' (ε) represent in Beer-Lambert's Law?

Molar absorptivity (ε) is a constant that indicates how strongly a substance absorbs light at a specific wavelength.

In Beer-Lambert's Law, how does increasing concentration affect absorbance?

Increasing the concentration of the substance in the solution results in a higher absorbance, assuming the path length and molar absorptivity remain constant.

What is the significance of Beer-Lambert's Law in analytical chemistry?

Beer-Lambert's Law is significant in analytical chemistry as it allows for the determination of concentration of an unknown solution by measuring its absorbance.

What is a chromophore?

A chromophore is a part of a molecule that has a color and is responsible for the absorption of light. It contains unsaturated groups that can absorb visible or ultraviolet light.

What is an example of a chromophore?

An example of a chromophore is the nitro group (-NO2), which can absorb UV light and can impart color to organic compounds.

What is an auxochrome?

An auxochrome is a functional group that does not have color by itself but can alter the color and absorption characteristics of a chromophore when attached.

What is an example of an auxochrome?

An example of an auxochrome is the hydroxyl group (-OH), which can modify the light absorption properties of a chromophore to allow for color development.

How do auxochromes affect chromophores?

Auxochromes, when attached to chromophores, increase the intensity of color and the ability to absorb light, thereby enhancing the color of the compound

What is UV spectroscopy?

UV spectroscopy is a technique used to measure the absorbance of ultraviolet light by a sample, which allows for the analysis of molecular structure and concentration.

What are the key components involved in UV spectroscopy?

Key components of UV spectroscopy include a light source that emits ultraviolet radiation, a sample holder (cuvette), a monochromator to select specific wavelengths, and a detector to measure absorbance.

What is the principle behind UV spectroscopy?

The principle behind UV spectroscopy is based on the absorption of UV light by molecules, leading to electronic transitions from lower energy states to higher energy states.

How does UV spectroscopy relate to molecular structure?

UV spectroscopy can provide information about the electronic structure of molecules, particularly those with conjugated systems, allowing for the identification of functional groups and the presence of specific chromophores.

What is Beer-Lambert's Law, and how does it apply to UV spectroscopy?

Beer-Lambert's Law states that absorbance (A) is proportional to the concentration (c) of the absorbing species, path length (l), and molar absorptivity (ε). This law is fundamental in UV spectroscopy for quantifying concentrations of substances in solution