There are three possible isomers, A, B and C, with the molecular formula C3H8O.
Isomers A and B are positional isomers of each other.
Isomer C is a functional group isomer of A and B.
A student uses the following equation to calculate that the percentage by mass of carbon in all three isomers is 60.0%.
Calculate the percentage by mass of hydrogen and oxygen in all three isomers.
The infrared spectrum of isomer C shown in Fig. 1.1 does not have a peak in the region of 3200 - 3600 cm-1.
Fig. 1.1
Bond | Functional groups containing the bond |
Characteristic infrared absorption range (in wavenumber) / cm–1 |
C−O | hydroxy, ester | 1040 – 1300 |
C=C | aromatic compound, alkene | 1500 – 1680 |
C=O | amide carbonyl, carboxyl ester |
1640 – 1690 1670 – 1740 1710 – 1750 |
C≡N | nitrile | 2200 – 2250 |
C−H | alkane | 2850 – 2950 |
N−H | amine, amide | 3300 – 3500 |
O−H | carboxyl hydroxy |
2500 – 3000 3200 – 3600 |
Isomers A and B both have a peak at 3200 - 3600 cm-1 in their infrared spectra.
State two possible chemical names for isomers A and B.
Isomer A has a major peak on its mass spectrum at m/e = 31.
Suggest, with a reason, which compound is isomer A.
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