Exam Questions Molecular Characterisation Chapter 12 - Chemistry 3 4e | Test Bank Burrows by Andrew Burrows. DOCX document preview.

Back to Product

Exam Questions Molecular Characterisation Chapter 12

Chapter 12: Molecular Characterisation

Test Bank

Type: multiple choice question

Title: Chapter 12 Question 01

1) By elemental analysis, the carbon content of an unknown compound was found to be 85.7%. From the following molecular formulae, (a)-(d), pick out the most likely formula for this unknown compound:

a. C4H8O

Section reference: 12.1 and 1.3

b. C5H8O

Section reference: 12.1 and 1.3

c. C6H12

Section reference: 12.1 and 1.3

d. C6H6

Section reference: 12.1 and 1.3

Type: multiple choice question

Title: Chapter 12 Question 02

2) Pick out the isotopic distribution pattern for 2-phenylpropanoic acid (hint: 1.1% of all carbon atoms have an atomic mass of 13).

a. 150 (M, 100%), 151 (1%), 152 (0.01%).

13C

Section reference: 12.1

b. 150 (M, 100%), 151 (5%), 152 (0.05%).

13C

Section reference: 12.1

c. 150 (M, 100%), 151 (10%), 152 (0.1%).

13C13C13C

Section reference: 12.1

d. 150 (M, 100%), 151 (20%), 152 (0.2%).

13C

Section reference: 12.1

Type: multiple choice question

Title: Chapter 12 Question 03

3) Pick out the molecular ion peak for a molecule containing a single nitrogen atom.

a. 84.

Section reference: 12.1

b. 93.

Section reference: 12.1

c. 108.

Section reference: 12.1

d. 114.

Section reference: 12.1

Type: matching question

Title: Chapter 12 Question 04

4) Match the following molecular formulae to the mass spectra A-C:

(A) A coordinate plane relates Relative intensity to m over z, where m over z is drawn along the horizontal axis. A vertical line 171 is drawn over the positive horizontal axis. (B) A coordinate plane relates Relative intensity to m over z, where m over z is drawn along the horizontal axis. Two vertical lines 170 and 172 of equal heights are drawn over the positive horizontal axis. (C) A coordinate plane relates Relative intensity to m over z, where m over z is drawn along the horizontal axis. Two vertical lines 170 and 172 are drawn over the positive horizontal axis. The height of 170 is more than line 172.

Section reference: 12.1

a. C7H7Br = B

b. C8H9NOCl = C

c. C10H21NO = A

Type: multiple choice question

Title: Chapter 12 Question 05

5) Which of the following bonds has the strongest IR absorption?

(A) A chemical structure shows S single bonded with H. (B) A chemical structure shows O single bonded with H. (C) A chemical structure shows N single bonded with H. (D) A chemical structure shows C single bonded with H.

a. A.

Section reference: 12.2

b. B.

Section reference: 12.2

c. C.

Section reference: 12.2

d. D.

Section reference: 12.2

Type: matching question

Title: Chapter 12 Question 06

6) Match the following aliphatic molecules to their infrared carbonyl stretching frequency:

(A) A chemical structure shows C double bonded with O and single bonded with R and C l. (B) A chemical structure shows C double bonded with O and single bonded with R and N M e 2. (C) A chemical structure shows C double bonded with O and single bonded with R and O M e 2. (D) A chemical structure shows C double bonded with O and single bonded with R and M e 2.

Section reference: 12.2

a. 1815 cm-1 = A

b. 1740 cm-1 = C

c. 1715 cm-1 = D

d. 1650 cm-1 = B

Type: multiple response question

Title: Chapter 12 Question 07

7) From the following molecules, pick out those which have no infrared absorption for a symmetrical stretch involving their corresponding double/triple bond(s). Please select all that apply.

(A) A chemical structure shows C double bonded with another C atom, where both the C atoms are single bonded with M e. (B) A chemical structure shows C triple bonded with another C atom, where both the C atoms are single bonded with M e. (C) A chemical structure shows a six membered C 6 ring. (D) A chemical structure shows M e single bonded with C, where C triple bonded with N.

a. A.

Section reference: 12.2

b. B.

Section reference: 12.2

c. C.

Section reference: 12.2

d. D.

Section reference: 12.2

Type: multiple response question

Title: Chapter 12 Question 08

8) From the following molecules, pick out those which have four proton signals in their 1H NMR spectrum. Please select all that apply.

(A) A chemical Structure shows C H 3 single bond C H 2 single bond C H 2 single bond C, where C is single bonded with two C H 3 and with C O 2 H. (B) A chemical structure shows three C H 3 single bond C single bond C H 2 single bond C H 2 single bond C O 2 H. (C) A chemical structure shows C H 3 single bond C H single bond C H 2 single bond C, where C is single bonded with two C H 3 and with C O 2 H. (D) A chemical structure shows two C H 3 single with C H single bond C H (C O 2 H) single bond C H, where C H is single bond with two C H 3. (E) A chemical structure shows H O 2 C single bond C H 2 single bond C (C H 3) (C H 3) single bond C H 2 single bond C H 3.

a. A.

Section reference: 12.3

b. B.

Section reference: 12.3

c. C.

Section reference: 12.3

d. D.

Section reference: 12.3

e. E.

Section reference: 12.3

Type: multiple response question

Title: Chapter 12 Question 09

9) From the following molecules, pick out those which do not have four proton signals in their 1H NMR spectrum. Please select all that apply.

(A) A chemical structure shows C H 3 single bond C H 2 single bond C H (C H 2) (C H 3) single bond C O single bond C l. (B) A chemical structure shows a six membered C 6 ring is fused with B r. (C) A chemical structure shows C single bonded with another C atom, where the first C atom is single bonded with C H 3 and F. The second C atom is single bonded with C H 3 and F. (D) A chemical structure shows M e O 2 C single bond C H (C H 3) single bond C H 2 single bond C H (C H 3) single bond C O 2 M e. (E) A chemical structure shows C H 3 single bond C O single bond O single bond C H, where C H is single bonded with two C H 3.

a. A.

Section reference: 12.3

b. B.

Section reference: 12.3

c. C.

Section reference: 12.3

d. D.

Section reference: 12.3

e. E.

Section reference: 12.3

Type: multiple choice question

Title: Chapter 12 Question 10

10) How many magnetically non-equivalent carbon atoms are there in toluene?

a. 4.

Section reference: 12.3

b. 5.

Section reference: 12.3

c. 6.

Section reference: 12.3

d. 7.

Section reference: 12.3

Type: multiple choice question

Title: Chapter 12 Question 11

11) How many magnetically non-equivalent carbon atoms are there in the following molecule?

A chemical structure shows a six membered C 6 ring single bonded with C atom, where C is single bonded with C H 3 and double bonded with O.

a. 5.

Section reference: 12.3

b. 8.

Section reference: 12.3

c. 4.

Section reference: 12.3

d. 6.

Section reference: 12.3

Type: multiple choice question

Title: Chapter 12 Question 12

12) How many magnetically non-equivalent carbon atoms are there in the following molecule?

A chemical structure shows a six membered C 6 ring double bonded with O, where C H 2 (P h) is single bonded with the same C atom at ortho position.

a. 7.

Section reference: 12.3

b. 8.

Section reference: 12.3

c. 10.

Section reference: 12.3

d. 11.

Section reference: 12.3

e. 13.

Section reference: 12.3

Type: multiple response question

Title: Chapter 12 Question 13

13) From the following molecules, pick out those which have six carbon signals in their 13C NMR spectrum. Please select all that apply.

(A) A chemical structure shows a six membered C 6 ring single bonded with C l, where O H is single bonded with the same C atom at meta position. (B) A chemical structure shows a six membered C 6 ring single bonded with C l, where C l is single bonded with the same C atom at meta position. (C) A chemical structure shows a six membered C 6 ring single bonded with O H. (D) A chemical structure shows a six membered C 6 ring single bonded with C l, where C l is single bonded with the same C atom at para position. (E) A chemical structure shows a six membered C 6 ring single bond with B r, where N O 2 is single bonded with the same C atom at ortho position.

a. A.

A chemical structure shows a six membered C 6 ring single bonded with C l, where O H is single bonded with C atom at meta position.

Section reference: 12.3

b. B.

A chemical structure shows a six membered C 6 ring single bonded with C l, where another C l is single bonded with C atom at meta position. A dashed horizontal is drawn through the ring, from bottom left to top right.

Section reference: 12.3

c. C.

A chemical structure shows a six membered C 6 ring single bonded with O H. A dashed vertical is drawn through the ring, from bottom to top.

Section reference: 12.3

d. D.

A chemical structure shows a six membered C 6 ring single bonded with C l, where another C l is single bonded with the C atom at para position. A dashed horizontal is drawn through ring, from left to right and a dashed vertical is drawn through the ring, from bottom to top.

Section reference: 12.3

e. E.

A chemical structure shows a six membered C 6 ring single bonded with B r, where N O 2 is single bonded with the C atom at ortho position.

Section reference: 12.3

Type: multiple choice question

Title: Chapter 12 Question 14

14) For an unknown compound, its proton and carbon NMR spectra showed three proton and four carbon signals, respectively. Pick out this unknown compound from the following molecules.

(A) A chemical structure shows a six membered C 6 ring single bonded with O H. (B) A chemical structure shows a six membered C 6 ring single bonded with O. (C) A chemical structure shows a six membered C 6 ring with double bond between C atom at ortho and meta position. (D) A chemical structure shows a six membered C 6 benzene ring.

a. A.

Section reference: 12.3

b. B.

Section reference: 12.3

c. C.

Section reference: 12.3

d. D.

Section reference: 12.3

Type: matching question

Title: Chapter 12 Question 15

15) The following molecules were examined by 1H NMR spectroscopy. Rank them in order of decreasing chemical shift for their methyl group (where 1 indicates the largest ppm and 3 indicates the smallest ppm):

(A) A chemical structure shows a six membered C 6 ring single bonded with C H 3, where N O 2 is single bonded with the C atom at para position. (B) A chemical structure shows a six membered C 6 ring single bonded with C H 3, where C l is single bonded with the C atom at para position. (C) A chemical structure shows a six membered C 6 ring single bonded with C H 3, where O H is single bonded with the C atom at para position.

Section reference: 12.3

a. 1 = Molecule A

b. 2 = Molecule B

c. 3 = Molecule C

Type: multiple choice question

Title: Chapter 12 Question 16

16) Which one of the following 1H NMR signals is a quintet?

(A) Five vertical lines of equals heights are drawn on a horizontal line. (B) Five vertical lines are drawn on a horizontal line. The heights are distributed from the middle line to the left and right symmetrically. (C) Five vertical lines are drawn on a horizontal line. The heights are distributed from the middle line to the left and right symmetrically. (D) Five vertical lines are drawn on a horizontal line. The heights are distributed from the middle line to the left and right symmetrically.

a. A.

pascals_triangle

Section reference: 12.3

b. B.

pascals_triangle

Section reference: 12.3

c. C.

pascals_triangle

Section reference: 12.3

d. D.

pascals_triangle

Section reference: 12.3

Type: multiple choice question

Title: Chapter 12 Question 17

17) By 1H NMR spectroscopy, what is the expected signal intensity for the eight lines of an octet?

a. 1:1:1:1:1:1:1:1.

pascalstriangle2

Section reference: 12.3

b. 1:2:3:4:4:3:2:1.

pascalstriangle2

Section reference: 12.3

c. 1:3:6:12:12:6:3:1.

pascalstriangle2

Section reference: 12.3

d. 1:5:10:15:15:10:5:1.

pascalstriangle2

Section reference: 12.3

e. 1:7:21:35:35:21:7:1.

pascalstriangle2

Section reference: 12.3

Type: multiple choice question

Title: Chapter 12 Question 18

18) How many degrees of unsaturation are there in a compound with the molecular formula C6H10NOCl?

a. 1.

Section reference: 12.4

b. 2.

Section reference: 12.4

c. 3.

Section reference: 12.4

d. 4.

Section reference: 12.4

e. 5.

Section reference: 12.4

Type: multiple choice question

Title: Chapter 12 Question 19

19) An unknown compound is analysed using NMR spectroscopy, generating the NMR spectra shown below. What is the structure of the unknown compound?

(A) A chemical structure shows a six membered C 6 ring attached with another six membered C 6 ring having two common C atoms. (B) A chemical structure shows a six membered C 6 ring attached with another six membered C 6 ring having two common C atoms. The right C 6 ring is double bonded with an O atom. (C) A chemical structure shows a six membered C 6 ring attached with another six membered C 6 ring having two common C atoms. The right C 6 ring is double bonded with an O atom. (D) A chemical structure shows a six membered C 6 ring attached with another six membered C 6 ring having two common C atoms.

1H NMR spectrum of unknown compound

An intensity curve is drawn over a horizontal axis, which ranges from 8.0 to 2.0 in decrements of 1.0. The curve attains three maxima points between 8.0 and 7.0, which are labelled 1.0, 2.0, and 1.04, from left to right. Another three maxima points are drawn between 3.0 and 2.0, which are labelled 12.16, 2.12, and 2.12, from left to right.

13C NMR spectrum of unknown compound

An intensity curve is drawn over a horizontal axis, which ranges from 200.0 to 20.0 in decrements of 10.0. The curve attains ten maxima points near 200.0, 155.0, five maxima between 130.0 and 135.0, 40.0, 30.0, and 20.0, from left to right.

1H NMR expansion 1

An intensity curve is drawn over a horizontal axis, which ranges from 8.1 to 7.1 in decrements of 0.1. The curve attains several high points near 8.0, 7.5, and 7.2, which are labelled 1, 1.04, and 2.2 from left to right.

1H NMR expansion 2

An intensity curve is drawn over a horizontal axis, which ranges from 3.1 to 2.0 in decrements of 0.1. The curve attains several high points near 3.05, 2.6, and 2.1, which are labelled 2.16, 2.12, and 2.12 from left to right.

a. A.

Section reference: 12.4

b. B.

Section reference: 12.4

c. C.

13C

Section reference: 12.4

d. D.

Section reference: 12.4

Type: multiple choice question

Title: Chapter 12 Question 20

20) An unknown compound is analysed using NMR spectroscopy, generating the NMR spectra shown below. What is the structure of the unknown compound?

(A) A chemical structure shows a six membered C 6 ring single bonded with C H (O H) (C H 3), where O M e is single bonded with the C atom at an ortho position. (B) A chemical structure shows a six membered C 6 ring single bonded with C H (O M e) (C H 3), where C l is single bonded with the C atom at an ortho position. (C) A chemical structure shows a six membered C 6 ring single bonded with C H (O M e) (C H 3), where O H is single bonded with the C atom at para position. (D) A chemical structure shows a six membered C 6 ring single bonded with C H (O H) (C H 3), where M e O is single bonded with the C atom at para position.

1H NMR spectrum of unknown compound

An intensity curve is drawn over a horizontal axis, which ranges from 7.0 to 1.0 in decrements of 1. The curve attains several high points near 6.9, 7, 5.0, 4.0, 2.0, and 1.5, which are labelled 1.95, 2.0, 1, 3.01, 0.98, and 3.05, from left to right.

13C NMR spectrum of unknown compound

A curve with very high intensity is drawn over a horizontal axis, which ranges from 170.0 to 10.0 in decrements of 10. The curve attains several high points near 160.0, 140.0, 130.0, 110.0, 70.0, 55.0, and 25.0.

1H NMR expansion 1

A curve with very high intensity is drawn over a horizontal axis, which ranges from 7.4 to 6.8 in decrements of 0.1. The curve attains several high points near 7.3 and 6.9, which are labelled 1.95 and 2.0 from left to right.

1H NMR expansion 2

Two curves are drawn over a horizontal axis, which ranges from 1.49 to 1.45 in decrements of 0.01. The first curve attains several high points near 1.48 and 1.465. The second curve starts from the starting point of the first curve, rises upward, bends upward between the high points of the first curve, intersects the curve at four points, and exits the top viewing window.

1H NMR expansion 3

Two curves are drawn over a horizontal axis, which ranges from 4.91 to 4.78 in decrements of 0.01. The first curve attains several high points near 4.87, 4.865, 4.84, and 4.82. The second curve starts near the starting point of the first curve, rises upward, intersects the curve at four points, and exits the top viewing window.

a. A.

Section reference: 12.4

b. B.

Section reference: 12.4

c. C.

Section reference: 12.4

d. D.

Section reference: 12.4

Type: multiple response question

Title: Chapter 12 Question 21

21) Select all of the following statements on expected IR frequencies that are true. Please select all that apply.

Section reference: 12.2

a. Acid chlorides will appear between 1820 – 1650 cm-1

b. Esters will appear between 3600 – 2500 cm-1

c. Phenols will appear between 3600 – 2500 cm-1

d. Aromatic C–H will appear between 3000 – 2850 cm-1

Type: multiple response question

Title: Chapter 12 Question 22

22) Select the following analytical techniques that would allow a pair of enantiomers of a molecule to be distinguished. Please select all that apply.

Section reference: 12.4

a. Chiral liquid chromatography

b. Mass Spectrometry

c. 1H-NMR

d. Polarimetry

Type: multiple choice question

Title: Chapter 12 Question 23

23) Select the molecule from the following structure that will have 6 carbon peaks, 4 hydrogen peaks in its NMR spectra.

(A) A chemical structure shows a six membered C 6 ring single bonded with M e, where M e is single bonded with the C atom at meta position. (B) A chemical structure shows a six membered C 6 ring single bonded with a C atom, where C is double bonded with O and single bonded with O M e. (C) A chemical structure shows a six membered C 6 ring single bonded with a C atom, where C is double bonded with O and single bonded with P h. (D) A chemical structure shows a six membered C 6 ring single bonded with a C atom, where C is double bonded with O and single bonded with H.

a. A

Section reference: 12.3

b. B

Section reference: 12.3

c. C

Section reference: 12.3

d. D

Section reference: 12.3

Type: multiple choice question

Title: Chapter 12 Question 24

24) Based on the information given, select the molecule to which it fits best.

7 carbon and 5 hydrogen peaks in its NMR spectra. MS 183.95 (100 %), 185.95 (100 %). IR frequency at 1740 cm-1

(A) A chemical structure shows a six membered C 6 ring single bonded with B r, where C O H is single bonded with the C atom at an ortho position. (B) A chemical structure shows a six membered C 6 ring single bonded with B r. (C) A chemical structure shows a six membered C 6 ring single bonded with C O H, where B r is single bonded with the C atom at para position. (D) A chemical structure shows a six membered C 6 ring single bonded with C O H, where C l is single bonded with the C atom at an ortho position.

a. A

Section reference: 12.4

b. B

Section reference: 12.4

c. C

Section reference: 12.4

d. D

Section reference: 12.4

Type: multiple response question

Title: Chapter 12 Question 25

25) Select the two major factors which influence chemical shifts from the list below. Please select all that apply.

Section reference: 12.3

a. Electron density

b. Anisotropic effects

c. Symmetry effects

d. Number of adjacent atoms

Document Information

Document Type:
DOCX
Chapter Number:
12
Created Date:
Aug 21, 2025
Chapter Name:
Chapter 12 Molecular Characterisation
Author:
Andrew Burrows

Connected Book

Chemistry 3 4e | Test Bank Burrows

By Andrew Burrows

Test Bank General
View Product →

$24.99

100% satisfaction guarantee

Buy Full Test Bank

Quick Navigation

Preview Document Info Connected Book Recommendations

Benefits

Immediately available after payment
Answers are available after payment
ZIP file includes all related files
Files are in Word format (DOCX)
Check the description to see the contents of each ZIP file
We do not share your information with any third party