- Created by: Maisie_Jane711
- Created on: 26-06-17 14:19
Uses of mass Spectrometry
- Detecting drugs in athletes
- Monitor/track pollutants
- Locate oil deposits by testing rock samples
- Assessing the damage on human genes via environment
- Identify the country of origin of diamonds
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- 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%
- 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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- 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
- 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.
- 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
- 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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- 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.
- Not carboxylic acid = nothing
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