11 mark
In HPLC, the mobile and stationary phases are
| Mobile phase | Stationary phase | |||
| ☐ | A | gas | liquid | |
| ☐ | B | gas | solid | |
| ☐ | C | liquid | gas | |
| ☐ | D | liquid | solid |
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Organic Analytical Techniques (Edexcel International A Level Chemistry)
Exam Questions
1
1 mark
1 markThe mass spectrum of the compound shown is obtained using a high resolution mass spectrometer.
What is the mass to charge ratio, m/ z, of the molecular ion of this compound?
[Ar values: H = 1.0078 C = 12.0000 O = 15.9949]
92.0261
92.0312
93.0339
93.0390
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2a1 mark
1 markThis question is about chromatography.
a)
A spot caused by an amino acid has moved 42 mm from the baseline of a paper chromatogram.
The Rf value for the amino acid under these conditions is 0.62.
What is the distance moved by the solvent?
The Rf value for the amino acid under these conditions is 0.62.
What is the distance moved by the solvent?
680 mm
68 mm
42 mm
26 mm
2b1 mark
b)
In gas chromatography, GC, which of these would be the most suitable carrier gas?
argon
hydrogen
methane
oxygen
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31 mark
How many peaks are there in the carbon-13 (13C) NMR spectrum of methylcyclohexane?
one
three
five
seven
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41 mark
In gas chromatography, a gas containing a mixture is passed over a liquid stationary phase. The main reason a mixture is separated into its components is because they have different
boiling temperatures
forces of attraction to the liquid
relative molecular masses
volatilities
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51 mark
In the high resolution proton NMR spectrum of propan-2-ol, CH3CHOHCH3 there are
one singlet, one doublet and a heptet
one singlet, two doublets and a heptet
two singlets and two triplets
three singlets and a quartet
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61 mark
A mixture of organic compounds was analysed using thin-layer chromatography.
The Rf value was 0.92 for one of the components in the mixture.
What can be deduced about the attractions between that component and the stationary and mobile phases?
| Attraction between component and stationary phase |
Attraction between component and mobile phase |
|||
| ☐ | A | strong | strong | |
| ☐ | B | strong | weak | |
| ☐ | C | weak | weak | |
| ☐ | D | weak | strong |
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