Assessing the damage on human genes via environment
Identify the country of origin of diamonds
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Mass Spectrometry
Can be used to find the molecular mass (Mr) ofa compound.
The peak with the heighest mass/charge value (x-axis) is equal to the Mr.
The peak at highest m/z also equals the molecular ion.
X = Mass/Charge, Y = Relative abundance%
High resolution:
Used to identify compounds that appear to have the same Mr when rounded.
Can measure the Mr to 4 decimal places.
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Infrared Spectroscopy
Pairs of atoms joined by a covalent bond continually vibrate at a specific frequency.
The vibrations have a frequency in the infrared regions of the electromagnetic spectrum.
A beam of inrared radiation is shone onto the compound with increases the amplitude of the vibration.
Each bond has adifferent natural frequency vibration, enabling chemists to identify what is present.
Y = Transmittance%, X = Wavenumber cm-1.
Functional groups can be found between 4000-1500cm-1.
The fingerprint region = below 1500cm-1, is unique to a particular compound and is used to find out what it is using a computed database. Extra peaks in this region shows impurities.
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Primary, Secondary or Tertiary alcohol
Test 1:
Add 10 drops of alcohol to 2cm3 of acidified potassium dichromate in a test tube.
Warm mixture gently in a hot water bath.
Primary/Secondary = Turns from orange to green(P-aldehyde formed,S-ketone formed) Tertiary = doesn't change.
Test 2:
Add excess alcohol to 2cm3 of acidified potassium dichromate in a round bottomed flask and attach to distillation apparatus.
Gently heat flask , alcohol gets oxidised and the product will be distilled immediatly. Ketone or aldehyde will be produced
Test 3:
Add 2cm3 of Fehling's or Benedict's solution to 5 drops of aldehyde/ketone and put into a warm water bath.
Aldehyde = brick red precipitate.
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Tollen's Reagent
Put 2cm3 of 0.10mol/dm-3 silver nitrate solution to a test tube.
Add a few drops of sodium hydroxide solution, light brown precipitate is formed.
Add dilute ammonia solution until precipitate dissolves.
Place test tube in hot water bath and add 10 drops of aldehyde/ketone and wait.
Aldehyde = silver mirror, reduced the Ag+ ions to silver atoms.
Ketone = nothing happens
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Test for alkenes
Testing for the presence of double bonds.
Add 2cm3 to of solution to a test tube with 2cm3 of bromine water.
Shake the test tube.
Alkene = orange to colourless
Alkane = nothing happens
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Test for carboxylic acids
Carboxylic acids react with carbonates to form a salt, carbon dioxide and water.
Add 2cm3 of solution to a test tube
Add a spatula of solid sodium carbonate .
If the solution fizzes you can test what it is by feeding the gas produced into lime water.
Carboxylic acid = Solution will fizz, lime water cloudy.
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