Modern Analytical Techniques

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Infrared radiation causes covalent bonds to vibrate more and ..?..
Absorb energy
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Absorption of Infrared radiation by atmospheric gases containing what bonds has been linked to global warming?
C=O, O-H and C-H
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What are some atmospheric gases?
Carbon dioxide, water vapour and methane
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What are some renewable energy methods which are starting to be used by the government?
Wind power, Solar power, Tidal power e.t.c
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What does infra red spectroscopy allow us to do and how?
Identify the type of organic compound something is by detecting the presence of specific covalent bonds within the compound
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How do we distinguish between bonds?
Each bond vibrates at a specific frequency so absorbs a specific frequency of infra red radiation
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What is an infra red spectrum?
A graph that shows the absorbance against wave number.
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What is wave number proportional to?
Frequency
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What part of the graph shows us which bonds are present?
The position of each inverted peak shows us what bonds are present in the compound
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What are some uses of IR spectroscopy?
Monitor gases causing air pollution, used in breathalyser to measure amount of ethanol in breath
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What is a mass spectrometer?
Device for measuring mass and abundance of isotopes in a sample
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How does it separate ions?
According to their mass to charge ratio (M/Z)
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Are heavy ions deflected more by the electromagnet at the bend or less than light ions?
Less
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What is a mass spectrum?
Graph showing % abundance against mass:charge ratio of an ion
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What is M/Z equal to when Z is one (which it always is)?
Relative isotopic mass
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How is the molecule ionised positively in mass spectrometry?
Hit by an electron which causes an electron to fall off from an atom on the molecule
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What is fragmentation?
The molecular ion can fragment into smaller ions and free radicals.
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Will fragmented ions and free radicals both be detected by the mass spectrometer?
No, only the fragmented ions will be
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What peak in an organic compounds' mass spectrum shows the Mr of the molecular ion?
The peak furthest right
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Why can there be sometimes be a little peak slightly further right than the Mr peak?
Carbon-13 being present
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When distinguishing a compound from a mass spectrum and infra red spectrum, what must we comment on?
Molecular ion mass, so Mr of compound, bonds that are and aren't present, at least two fragment ions and their possible structure, and finally the name of the compound
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Other cards in this set

Card 2

Front

Absorption of Infrared radiation by atmospheric gases containing what bonds has been linked to global warming?

Back

C=O, O-H and C-H

Card 3

Front

What are some atmospheric gases?

Back

Preview of the front of card 3

Card 4

Front

What are some renewable energy methods which are starting to be used by the government?

Back

Preview of the front of card 4

Card 5

Front

What does infra red spectroscopy allow us to do and how?

Back

Preview of the front of card 5
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