Spectroscopy 2

<p>Vibrational energy associated with molecular bonds (A)</p> Signup and view all the answers

<p>Compressing into a pellet with potassium bromide (B)</p> Signup and view all the answers

<p>Functional groups within a molecule (C)</p> Signup and view all the answers

<p>They are discrete and associated with molecular bonds. (A)</p> Signup and view all the answers

<p>To analyze chemical reactions in real-time. (A)</p> Signup and view all the answers

<p>Asymmetrical vibrations (D)</p> Signup and view all the answers

<p>The molecule must be polarisable (D)</p> Signup and view all the answers

<p>Symmetrical molecules do not display absorbance in the IR region unless asymmetrical vibrations occur. (D)</p> Signup and view all the answers

<p>They possess multiple bonds and complex structures. (B)</p> Signup and view all the answers

<p>Anti-symmetric stretching (C)</p> Signup and view all the answers

<p>To analyze vibrational transitions of drug molecules (B)</p> Signup and view all the answers

<p>Forming the sample into a thin film or pellet (A)</p> Signup and view all the answers

<p>Anti-symmetric stretching results in a net dipole change. (B)</p> Signup and view all the answers

<p>To identify functional groups and confirm drug identity (C)</p> Signup and view all the answers

<p>The complexity of the spectrum (C)</p> Signup and view all the answers

<p>O-H (A)</p> Signup and view all the answers

<p>They create additional absorption bands not seen in pure compounds (C)</p> Signup and view all the answers

<p>Mixing with a mulling agent or KBr (B)</p> Signup and view all the answers

<p>The purity and concentration of the sample (B)</p> Signup and view all the answers

<p>C-H bond is the weakest among them (C)</p> Signup and view all the answers

<p>Vibrational transitions (B)</p> Signup and view all the answers

<p>It has standard IR spectra for confirming drug identity (C)</p> Signup and view all the answers

<p>Gases absorb less IR radiation than liquids (C)</p> Signup and view all the answers

<p>The lighter the atom, the higher the frequency of absorption.</p> Signup and view all the answers

<p>Stronger bonds result in higher absorption frequencies.</p> Signup and view all the answers

<p>Correlation charts help identify specific functional groups based on their characteristic absorption frequencies.</p> Signup and view all the answers

<p>It indicates that different molecules can possess similar functional groups, making spectral analysis complex.</p> Signup and view all the answers

<p>It provides insight into how these molecules vibrate and absorb IR radiation, aiding in their identification.</p> Signup and view all the answers

<p>Only asymmetrical vibrations absorb infrared radiation.</p> Signup and view all the answers

<p>Complicated compounds have more than one mode of vibration, leading to many absorbance bands.</p> Signup and view all the answers

<p>A molecule must be polarisable and have asymmetrical vibrations to absorb IR radiation.</p> Signup and view all the answers

<p>Symmetrical stretching involves equal movement of atoms in opposite directions, while anti-symmetric stretching involves unequal movements.</p> Signup and view all the answers

<p>Each type of vibration corresponds to a specific frequency of radiation absorbed.</p> Signup and view all the answers

<p>Asymmetrical molecules or symmetrical molecules undergoing specific bending or stretching can exhibit IR absorptions.</p> Signup and view all the answers

<p>Bending vibrations can allow symmetrical molecules to absorb infrared light if they can induce a dipole.</p> Signup and view all the answers

<p>Common vibrations occur at approximately 3756 cm-1 for stretching and 1595 cm-1 for bending.</p> Signup and view all the answers

<p>Vibrational and rotational transitions.</p> Signup and view all the answers

<p>The energy required for vibrational transitions is smaller than that for electronic transitions.</p> Signup and view all the answers

<p>Infrared Spectroscopy produces absorption spectra, which are plotted as wavenumber (cm-1).</p> Signup and view all the answers

<p>It provides characteristic absorption peaks corresponding to specific functional groups.</p> Signup and view all the answers

<p>The appearance of an IR spectrum is due to the transitions of molecules between discrete vibrational energy levels.</p> Signup and view all the answers

<p>Vibrational energy levels are set values that only assume certain discrete levels within electronic states.</p> Signup and view all the answers

<p>To perform qualitative fingerprint checks for the identity of raw materials.</p> Signup and view all the answers

<p>Infrared Spectroscopy can analyze samples in solid and semi-solid states, such as creams and tablets.</p> Signup and view all the answers

<p>The fingerprint region is typically between 1500 and 400 cm-1.</p> Signup and view all the answers

<p>The C-H bond requires the least energy to stretch.</p> Signup and view all the answers

<p>Symmetrical molecules generally do not absorb IR radiation effectively.</p> Signup and view all the answers

<p>The BP provides standard IR spectra of compounds for comparison to ensure drug authenticity.</p> Signup and view all the answers

<p>Solvent residues can introduce additional absorption peaks not found in a pure compound.</p> Signup and view all the answers

<p>This region is associated with stretching vibrations of diatomic units.</p> Signup and view all the answers

<p>The complexity and unique patterns in this region make precise assignments difficult.</p> Signup and view all the answers

<p>Solid samples are often ground to a paste and mixed with a mulling agent like nujol.</p> Signup and view all the answers

<p>The O-H bond is stronger than both N-H and C-H bonds.</p> Signup and view all the answers

<p>A molecule must have a changing dipole moment during vibration.</p> Signup and view all the answers

A technique that analyzes the vibrational energy of bonds in molecules using infrared light.

The region in an IR spectrum (4000-1500 cm⁻¹) where stretching vibrations of diatomic units are usually found.

The region in an IR spectrum (1500-400 cm⁻¹) characterized by complex patterns of absorption bands, used for confirming structures.

A vibrational mode of molecules where atoms vibrate along the bond axis, giving characteristic absorptions in IR spectra.

The amount of energy required to break a chemical bond.

The frequency of infrared light absorbed by a bond, related to the bond strength.

Techniques for preparing liquid samples for IR analysis, such as spreading a drop between IR plates.

Methods for preparing solid samples for IR analysis, including grinding, mulling, and KBr pellet techniques.

Standard reference for drug identification and analysis, using IR spectra.

Using IR spectroscopy to detect and quantify impurities in a sample by observing differing absorption bands.

A technique that analyzes the absorption of infrared radiation by molecules to identify functional groups and bonds.

Changes in the vibrational energy levels of molecules, caused by absorption of infrared radiation.

A plot of the amount of infrared radiation absorbed by a molecule versus wavenumber(cm-1).

A measurement of the frequency of infrared radiation, equivalent to the reciprocal of wavelength.

Specific groups of atoms within a molecule that determine its chemical properties and reactions.

Changes in the electronic energy levels of molecules, as seen by UV-Vis spectroscopy.

Technique analyzing electronic transitions within molecules using specific electromagnetic spectrum.

Methods needed to put a sample in a form suitable for analysis by IR spectroscopy, including solids, semi-solids, etc

Infrared (IR) radiation has lower energy compared to ultraviolet (UV) radiation.

Molecules can vibrate in different ways, including stretching and bending of bonds. Each vibration corresponds to a specific energy level.

Symmetrical stretching involves equal movement of atoms on both sides of a bond. Asymmetrical stretching has unequal movement.

For a molecule to absorb IR radiation, it needs to be 'polarisable' - meaning the electron distribution can change during vibration.

A graph plotting absorbance against frequency (or wavelength) of IR radiation. Each peak corresponds to a specific vibration.

Complex molecules have many different vibrational modes, leading to multiple peaks in the IR spectrum.

Only asymmetric stretching vibrations absorb IR radiation because they create a changing dipole moment.

By analyzing the peaks in an IR spectrum, we can identify the functional groups and structure of a molecule.

UV-Vis spectroscopy studies how molecules absorb UV and visible light, causing electrons to jump to higher energy levels. This helps determine the structure and properties of molecules.

IR spectroscopy analyzes how molecules absorb infrared radiation, causing their bonds to vibrate. This helps identify functional groups and determine the molecule's structure.

A molecule is IR active if its vibrations create a changing dipole moment. This means the charge distribution within the molecule changes during vibration.

Molecules can vibrate in two main ways: stretching, where the bond length changes, and bending, where the bond angle changes.

The fingerprint region (1500-400 cm⁻¹) in an IR spectrum shows complex patterns of absorption bands unique to each molecule. It's like a fingerprint for identifying specific compounds.

IR spectroscopy is used to identify raw materials, confirm product purity, and identify functional groups in drug molecules, ensuring quality control and patient safety.

Samples can be prepared as liquids, solids, or pastes. Liquid samples can be placed between salt plates. Solids can be ground and mixed with KBr to make a pellet.

Different types of bonds absorb IR radiation at specific frequencies. By analyzing the peak positions in an IR spectrum, we can identify the functional groups present in a molecule and deduce its structure.

Infrared (IR) radiation has lower energy compared to ultraviolet (UV) radiation. It causes molecular vibrations rather than electronic transitions.

The vibration where atoms move along the bond axis, either symmetrically or asymmetrically.

The vibration where the bond angle changes, causing the molecule to bend or twist.

The ability of a molecule's electron distribution to change during vibration.

For a molecule to absorb IR radiation, it must be polarisable, meaning its electron distribution changes during vibration.

Complicated molecules have many different possible vibrations, leading to numerous peaks in the IR spectrum.

The frequency of infrared light absorbed by a molecule is influenced by the mass of the atoms and the strength of the bond.

Lighter atoms vibrate at higher frequencies, resulting in a higher absorption frequency in the IR spectrum.

Stronger bonds vibrate at higher frequencies, leading to higher absorption frequencies in the IR spectrum.

Characteristic absorption frequencies in an IR spectrum associated with specific functional groups in a molecule.

Tables that list group frequencies for different functional groups, helping to interpret IR spectra and identify unknown compounds.

Stronger bonds require more energy to stretch, resulting in absorption at higher frequencies in the IR spectrum.

IR spectra can show the presence of impurities in a compound by revealing additional absorption bands not present in a pure sample.

IR spectroscopy is versatile and can analyze various forms of samples, including solids, liquids, and gases.

UV-Vis spectroscopy analyzes electronic energy transitions, while IR spectroscopy studies vibrational energy changes – UV has higher energy than IR.