Organic Synthesis and Analysis Flashcards
What happens to a molecule when it encounters infrared radiation?
Its bonds may stretch or bend.
What part of the infrared spectra is called the finger print region?
The region below 1500
What do we use infrared spectra for?
To show the presence of functional groups.
How does infrared spectroscopy work?
By passing a beam of IR radiation through a sample. It’s then absorbed by the COVALENT BONDS of the molecules increasing their vibrational energy. Different bonds absorb different wavelengths. Bonds in different environments in a molecule absorb different wavelengths too.
What property of certain nuclei (such as H+) allow us to perform NMR spectroscopy?
They can spin.
Explain what happens when a sample containing hydrogen atoms is placed in a strong magnetic field.
They flip to align with or against the magnetic field.
What does TLC stand for?
Thin layer chromatography.
What is the ‘stationary phase’ in chromatography?
When the molecules can’t move. This must be a solid or a liquid held in a solid.
What is the ‘mobile phase’ in chromatography?
When the molecules are able to move. This is always when they are a liquid or a gas.
Why do different chemicals travel up the plate at different rates?
They dissolve at different rates. The more soluble they are the quicker they dissolve into the solvent and go into the mobile phase. Mass also effects this.
What is the retardation factor (Rf)?
The measure of how far a compound moves compared to the distance traveled by the solvent.
What is the formula for the retardation factor?
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What are the three types of chromatography?
TLC (thin layer chromatography), gas chromatography, and HPLC (high performance liquid chromatography)
What is a chiral centre?
A carbon that has a different functional group on each bond.
Note: it doesn’t include double bonds.)
Give an example of addition polymerisation.
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