2014年11月IB化学SL真题下载-Paper3
1. The mass spectrum and infrared (IR) spectrum of a compound are shown below.
(a) (i) State the information about this particular compound that can be derived from the mass spectrum and outline how it is found.
(ii) Suggest how the fragment with m/z = 43 is formed from the original molecule.
(b) (i) Use the IR spectrum in the region 1600 – 1800 cm–1 to deduce one functional group that is present in the compound and one group that is absent.
Present:
Absent:
(ii) The molecular formula of the compound is C3H6O2. Explain, with reference to another region of the IR spectrum, why the compound could not be propanoic acid, CH3CH2COOH.
(iii) Deduce the structures of two possible isomers of propanoic acid consistent with the IR spectrum.
(c) 1H NMR spectroscopy is often very useful in distinguishing between closely related compounds such as those above.
(i) State the region of the electromagnetic spectrum that is used in this technique.
(ii) The structures of two other closely related compounds are shown below.
Discuss how you would expect the 1H NMR spectra of these two compounds to differ, using Table 18 of the Data Booklet.
2. Waste water from an abandoned copper mine is suspected of polluting a community’s drinking water supply, causing concern that the concentration of dissolved copper compounds might exceed the legal limit of 1.3 ppm.
(a) State the most appropriate analytical technique to investigate the concentration of copper in the water supply.
(b) Outline how this technique could be used to determine the concentration of copper ions present in a particular sample of water.
3. The principles of chromatography can be demonstrated using paper chromatography to analyse the ink of a pen, using propanone as the mobile phase.
(a) State how you could tell whether the ink was a single substance or a mixture of components.
(b) Explain how paper chromatography separates the components.
(c) The Rf value of the components of the ink could be measured. Define the term Rf .
(d) State one factor that would alter the Rf value of a particular component.
2014年11月IB化学SL真题余下省略！
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