Infrared spectroscopy is used to identify the functional groups present in a compound.

Identify the functional groups responsible for the peaks labelled X and Y.

Which of the following compounds could produce the IR spectrum shown in part a)?

Explain how the two isomers shown in the diagram below can be distinguished using IR spectroscopy.

Which functional group is present in the compound whose IR spectrum is shown in the diagram below?

The diagram below shows the mass spectrum of 1-iodopentane.

What information can be determined by the peak labelled X at m/z = 198?

Write the structural formulae of the ions responsible for the peaks labelled Y and Z.

The compound shown in the diagram below is an isomer of 1-iodopentane.

Name this compound.

Give one similarity and one difference between the mass spectra of 1-iodopentane and its isomer shown in part c).

The diagram below shows the mass spectrum of an alkene.

What is the molecular mass of the alkene?

The empirical formula of the alkene is CH₂.

Determine the molecular formula of the alkene.

The compound with molecular formula C₆H₁₂ was found to be hex-2-ene.

Suggest the structures of the ions responsible for the peaks labelled X and Y.

Complete the table below to show the type of bond and functional group responsible for each of the three absorptions.

The diagram below shows the infrared spectrum of 2-bromopropane. The peak due to the C-Br bond has been labelled.

2-Bromopropane is then reacted with aqueous NaOH to form an alcohol.

Explain how IR spectroscopy could be used to show the reaction is complete.

An organic compound is analysed and found to have the following percentage composition by mass:

C 70.58%, H 5.92%, O 23.50%

The mass spectrum of this compound is shown in the diagram below.

Use this information to determine the molecular formula of this compound.

Compound X contains a carbon-carbon double bond (C=C) but does not show E/Z stereoisomerism. It has empirical formula C₂H₃O.

Compound X was analysed by infrared spectroscopy and mass spectrometry and the results are shown in the diagrams below.

Use the information above to determine:

• the molecular formula of X,
• the ions responsible for the peaks labelled X and Y in the mass spectrum,
• the structure of X.

The mass spectrum of an organic molecule shows the ratio of the heights of the M and M+1 peak to be 22.1:0.7.

Calculate the number of carbon atoms, n, in the molecule.

Test-tube reactions can be used as a fast and effective method for distinguishing between organic compounds.

Give a reagent that could be used to distinguish between butane and but-1-ene, and state the observation that would be made with each compound.

Identify which of the following isomers would react when heated with acidified potassium dichromate(VI), and state the observation that would be made.

Identify which of the following isomers would react with Tollens' reagent, and state the observation that would be made.

Describe how infrared spectroscopy could be used to distinguish between the following isomers.

Compound M is an unknown organic compound with the following percentage composition by mass:

carbon 54.5%; hydrogen 9.10%; oxygen 36.4%

Calculate the empirical formula of compound M.

Use the mass spectrum of compound M, shown in the diagram below, and your answer to part a), to determine the molecular formula of M.

The infrared spectrum of compound M shows a broad peak at 3500 cm^-1 and a sharp peak at 1700 cm^-1.

Identify the bond responsible for producing each peak.

Compound M is a neutral compound, has no effect on Tollens' reagent, and turns acidified potassium dichromate(VI) from orange to green.

Use this information and your answer to part c) to name the two functional groups in compound M.

A student found 4 unlabelled bottles of liquid each containing a different organic compound. The compounds were known to be butan-1-ol, butanal, butanoic acid and 1-bromobutane.

Describe 4 test tube reactions that could be used to identify each compound. Include the name of the reagent(s) and the expected observation for each compound.

The compounds shown below are isomers.

Suggest and explain which of these structures could produce the infrared spectrum shown in the diagram below.

Identify the functional group(s) shown in the infrared spectrum in the diagram below. Justify your answer.

Compound W has the following percentage composition by mass: C 66.7%; H 11.1%; O 22.2%, and produces the infrared spectrum shown in the diagram below.

The molecular mass of W is 72.

Suggest two possible structures for compound W.

Compound Z contains only the elements carbon, hydrogen and oxygen, and its mass spectrum is shown in the diagram below.

Identify the m/z value of the molecular ion.

Suggest a formula for the ion responsible for the peak at m/z = 31 in the mass spectrum in part b).

Suggest the molecular formula of compound Z using your answers to parts b) and c).

Compound V is an E stereoisomer and has the following percentage composition by mass: C 68.6%; H 8.6%; O 22.8%. The infrared and mass spectra of compound V are shown in the diagrams below.

The peak with the greatest relative intensity (m/z = 41) in the mass spectrum is caused by the loss of a functional group from the molecular ion.

Determine the structure of compound V.

Which compound would produce the infrared spectrum shown in the diagram below?

The structure of the compound geraniol is shown in the diagram below.

The mass spectrum of geraniol is shown in the diagram below.

Use both diagrams to explain how the molecular mass of geraniol can be confirmed by mass spectrometry.