1 How many molecular ion peaks (parent ion peaks) are in the mass spectrum of 1,2-dibromoethane? ssume the only isotopes present are 1 H, 12, 79 r and 81 r. 1 2 3 4 2 This question is about two isomeric alcohols and two isomeric carbonyl compounds. utan-1-ol, H 3 H 2 H 2 H 2 OH utan-2-ol, H 3 H 2 H(OH)H3 utanal, H 3 H 2 H 2 HO utanone, H 3 H 2 OH 3 (a) Which of these compounds would not produce a colour change when heated with acidified sodium dichromate(vi) solution? utan-1-ol utan-2-ol utanal utanone (b) Which compound could give a peak at m/e = 31 in its mass spectrum? utan-1-ol utan-2-ol utanal utanone (c) Which compound could not give a peak at m/e = 43 in its mass spectrum? utan-1-ol utan-2-ol utanal utanone PhysicsndMathsTutor.com
(d) The infrared spectrum of one of these compounds is given below. 100 Transmittance (%) 50 0 4000 3000 2000 1500 1000 500 Wavenumber / cm 1 Use the infrared absorptions, in wavenumbers, to identify the compound. ond Wavenumber range / cm 1 O H (alcohol) 3750 3200 H (alkane) 2962 2853 H (aldehyde) 2900 2820 and 2775 2700 =O (aldehyde or ketone) 1740 1680 The compound with this IR spectrum is butan-1-ol. butan-2-ol. butanal. butanone. (Total for Question = 4 marks) PhysicsndMathsTutor.com
3 The correct sequence for the processes that occur in a mass spectrometer is vaporization, ionization, acceleration, deflection and detection. vaporization, acceleration, ionization, deflection and detection. ionization, vaporization, acceleration, deflection and detection. ionization, vaporization, deflection, acceleration and detection. 4 Which of the following ions would be deflected most in a mass spectrometer? 35 l + 37 l + 37 l 2+ 35 ( l 37 l) + 5 In a mass spectrum of butane, 4 H 10, where would a peak be seen for the molecular ion if it had a charge of 2+? 29 56 58 60 PhysicsndMathsTutor.com
6 The formula for oleyl alcohol, which is present in sperm whale oil and was used as a lubricant, is shown below. H 3 (H 2 ) 7 H (H 2 ) 7 H 2 OH H (a) The systematic name for oleyl alcohol is E-octadec-9-en-1-ol. Z-octadec-9-en-1-ol. E-octadec-8-en-1-ol. Z-octadec-8-en-1-ol. (b) Which intermolecular forces are present between oleyl alcohol molecules? London forces only Hydrogen bonds and London forces only Hydrogen bonds and permanent dipole dipole forces only Hydrogen bonds, permanent dipole dipole and London forces (c) Which of the following is the most likely structure of the species to cause a peak at m/e 31 in the mass spectrum of oleyl alcohol? H 3 O H 2 OH H 3 O + H 2 OH + (d) What would you expect to see if oleyl alcohol is tested separately with bromine water and heated with acidified sodium dichromate(vi) solution? romine water cidified sodium dichromate(vi) solution ecolorises Turns green No colour change No colour change ecolorises No colour change No colour change Turns green PhysicsndMathsTutor.com (Total for Question = 4 marks)
7 romine has two isotopes with relative isotopic masses 79 and 81. Which of the following values for mass/charge ratio could correspond to a peak in the mass spectrum of bromine, r 2? You should assume the ions detected have a single positive charge. 79.9 80 159 160 8 The concentration of a solution of potassium iodate(v) can be determined by the liberation of iodine, followed by titration with sodium thiosulfate. suitable indicator is methyl orange. phenolphthalein. starch. universal indicator. 9 The thermite reaction, shown below, is a useful industrial process. The iron in this reaction undergoes Fe 2 O 3 (s) + 2l(s) 2Fe(l) + l 2 O 3 (s) disproportionation. oxidation. redox. reduction. PhysicsndMathsTutor.com
10 This question is about the following isomeric compounds with the molecular formula 4 H 8 O and molar mass 72 g mol 1. H 3 H 2 H 2 HO (H 3 ) 2 HHO H 3 H 2 OH 3 H 3 H HH 2 OH (a) Which compound would you expect to give a peak at m/e = 41 in its mass spectrum? (b) Which compound would NOT react with an acidified solution of potassium dichromate(vi)? (c) Which compound would give a pale yellow precipitate when reacted with iodine in alkaline solution? (d) Which compound can be reduced to give a chiral product? PhysicsndMathsTutor.com
(e) Which compound would NOT react with hydrogen cyanide under suitable conditions to form a hydroxynitrile? (Total for Question = 5 marks) 11 There would be a major peak in the mass spectrum for butan-1-ol, H 3 H 2 H 2 H 2 OH, but not for butan-2-ol, H 3 H 2 H(OH)H 3, at m/e value 15 17 29 43 (Total for Question 1 mark) 12 How many molecular ion peaks (parent ion peaks) occur in the mass spectrum of 1,2-dibromoethane, H 2 rh 2 r? ssume the only isotopes present are 1 H, 12, 79 r and 81 r. 1 2 3 4 (Total for Question 1 mark) PhysicsndMathsTutor.com
13 Which of the following features is shown by the mass spectra of propanone and propanal? O H 3 H 3 propanone O H 3 H 2 H propanal m/e of the molecular ion Fragmentation pattern same same same different different same different different PhysicsndMathsTutor.com
14 The mass spectrum for a sample of a metal is shown below. relative abundance 70 30 63 mass/charge ratio 65 The relative atomic mass of the metal is 63.2 63.4 63.6 64.0 15 Which of the following ions would undergo the greatest deflection in a mass spectrometer? 35 l 2+ 35 l + 37 l + 35 l 37 l + PhysicsndMathsTutor.com
16 Which of the following values for the mass/charge ratio for singly charged ions would be present in the mass spectrum of propanal, H 3 H 2 HO, but not of propanone, H 3 OH 3? 15 29 43 58 17 Propanal, H 3 H 2 HO, and propanone, H 3 OH 3, are isomers, but only propanal has a significant peak in its mass spectrum at mass/charge ratio 15 29 43 58 18 Two ketones, H 3 OH 2 H 2 H 3 and H 3 H 2 OH 2 H 3, both have M r 86. Which peak due to fragmentation into singly charged ions would you expect to be present in the mass spectrum of one but not the other? 71 57 43 (Total for Question 1 mark) PhysicsndMathsTutor.com