This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

Copyright © 2019 by NCEES. All rights reserved.

All NCEES sample questions and solutions are copyrighted under the laws of the United States. No part of this publication
may be reproduced, stored in a retrieval system, or transmitted in any form or by any means without the prior written
permission of NCEES. Requests for permissions should be addressed in writing to permissions@ncees.org.

ISBN 978-1-947801-09-7

Printed in the United States of America

1st printing August 2019
This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

CONTENTS

Introduction to NCEES Exams ................................................................ 1

About NCEES
Exam Format
Examinee Guide
Scoring and reporting
Updates on exam content and procedures

Exam Specifications.......................................................................... 3

PE Chemical Practice Exam ............................................................. 9

PE Chemical Solutions ................................................................... 69

iii
This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

About NCEES
NCEES is a nonprofit organization made up of the U.S. engineering and surveying licensing boards in
all 50 states, the U.S. territories, and the District of Columbia. We develop and score the exams used
for engineering and surveying licensure in the United States. NCEES also promotes professional
mobility through its services for licensees and its member boards.

Engineering licensure in the United States is regulated by licensing boards in each state and territory.
These boards set and maintain the standards that protect the public they serve. As a result, licensing
requirements and procedures vary by jurisdiction, so stay in touch with your board
(ncees.org/licensing-boards).

Exam Format
The PE Chemical exam is computer-based. It contains 80 questions and is administered year-round via
computer at approved Pearson VUE test centers. A 9-hour appointment time includes a tutorial, the
exam, and a break. You’ll have 8 hours to complete the actual exam.

In addition to traditional multiple-choice questions with one correct answer, the PE Chemical exam
uses common alternative item types such as
• Multiple correct options—allows multiple choices to be correct
• Point and click—requires examinees to click on part of a graphic to answer
• Drag and drop—requires examinees to click on and drag items to match, sort, rank, or label
• Fill in the blank—provides a space for examinees to enter a response to the question

To familiarize yourself with the format, style, and navigation of a computer-based exam, view the
demo on ncees.org/ExamPrep.

Examinee Guide
The NCEES Examinee Guide is the official guide to policies and procedures for all NCEES exams.
During exam registration and again on exam day, examinees must agree to abide by the conditions in
the Examinee Guide, which includes the CBT Examinee Rules and Agreement. You can download the
Examinee Guide at ncees.org/exams. It is your responsibility to make sure you have the current
version.

Scoring and reporting

Results for computer-based exams are typically available 7–10 days after you take the exam. You will
receive an email notification from NCEES with instructions to view your results in your MyNCEES
account. All results are reported as pass or fail.

Updates on exam content and procedures

Visit us at ncees.org/exams for updates on everything exam-related, including specifications, exam-
day policies, scoring, and corrections to published exam preparation materials. This is also where you
will register for the exam and find additional steps you should follow in your state to be approved for
the exam.

1
This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL PRACTICE EXAM

•
•

9
This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL PRACTICE EXAM

1. Orimulsion is a tar-like bitumen that uses an emulsifying agent to produce a liquid. This blend
(15 wt% emulsifying agent) can be substituted for oil in utility burners.

Data on orimulsion (exclusive of emulsifying agent):

Heating Value: 16,800 Btu/lb (dry and ash-free)

Content, wt%:
Ash: 12.1
Moisture: 10.9
Organic: 77.0

The emulsifying agent has no heating value. The heating value (Btu/lb) of the as-delivered
emulsified fuel is most nearly:

o A. 11,000
o B. 12,900
o C. 14,300
o D. 16,800

2. The table below gives the characteristics of a gas stream flowing at a rate of 100 lb moles/hr.

Component MW mol%
N2 28 80
SO2 64 20

The N2 flow rate (lb/hr) is most nearly _______.

Copyright © 2019 by NCEES 10 NEXT→

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL PRACTICE EXAM

20. A wastewater bog exhibits the following conditions:

pH = 6
Hg2+ = 5 × 10–25 mol/L
Dissolved organic sulfur RSH5– = 0.01 mol/L

The following chemical reaction applies:

RSH5– + Hg2+ ⇌ RSHg4– + H+

The stability constant kequil for this reaction is 1012. The total concentration of dissolved
mercury (mol/L) in this water is most nearly:

o A. 5 × 10–25
o B. 5 × 10–21
o C. 5 × 10–15
o D. 5 × 10–9

21. An elementary reversible reaction of the form A ⇌ B is also accompanied by an elementary first-
order decomposition reaction of the form A → C. The rate constants for the forward and reverse
reactions of the reversible reaction are 0.4 hr–1 and 0.1 hr–1, respectively. Similarly, the rate
constant for the decomposition reaction is 0.2 hr–1. If the initial reaction mixture contains only
Reactant A at a concentration of 1.5 g mol/L, then the equilibrium or steady-state (as t → ∞)
concentration of Product B (g mol/L) would be most nearly:

o A. 0
o B. 0.9
o C. 1.2
o D. 1.3

Copyright © 2019 by NCEES 25 NEXT→

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL PRACTICE EXAM

57. An ammonia-water stream (essentially at its bubble point) is processed in a trayed stripping
column with an external kettle reboiler to recover the majority of the ammonia. A constant
molal overflow simulation provides the following information:

Overhead ammonia mole fraction 0.95

Bottoms ammonia mole fraction 0.01
Feed ammonia mole fraction 0.40

The reboiler boilup ratio (V/B) for these conditions is most nearly:

o A. 0.41
o B. 0.58
o C. 0.71
o D. 1.41

Copyright © 2019 by NCEES 48 NEXT→

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL PRACTICE EXAM

62. A mixture of vinyl acetate (nbp: 346 K), acetic acid (nbp: 391 K), and water is distilled in a
continuous compound multitray column. Computer simulation results are shown in the figure
superimposed on a mole fraction L-L phase diagram. On the phase diagram below, mark the
composition (mole fractions) of the aqueous distillate product.

Copyright © 2019 by NCEES 54 NEXT→

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL PRACTICE EXAM

65. A reactor is to be installed at a manufacturing plant. For pressure relief due to a multiphase-
runaway reaction, the P&ID indicates a rupture disc on the reactor with discharge noted as
"vent to a safe location." Which of the following is most likely to be regarded as a "safe
location" for the vent discharge?

o A. Grade level adjacent to reactor

o B. Blowdown tank vented to the flare

o C. Flare header

o D. Vertically 10 ft above the reactor

66. OSHA standards define confined space as follows:

OSHA Standard 1910.146 (29CFR)

Permit-required confined space (permit space) means a confined space that has one or more of
the following characteristics:
(1) Contains or has a potential to contain a hazardous atmosphere;
(2) Contains a material that has the potential for engulfing an entrant;
(3) Has an internal configuration such that an entrant could be trapped or asphyxiated by
inwardly converging walls or by a floor which slopes downward and tapers to a smaller
cross-section; or
(4) Contains any other recognized serious safety or health hazard.

Under OSHA regulations, which of the following are considered to be permit-required confined
spaces that require special entry procedures?

Select all that apply.

□ A. 8-ft-diameter × 40-ft-tall distillation column

□ B. 8-ft × 8-ft × 6-ft-deep cooling tower basin
□ C. 8-ft × 8-ft × 10-ft-tall electrical room
□ D. 3-ft-diameter × 6-ft-tall boiler steam drum
□ E. 3-ft-high tank farm dike
□ F. 5-ft-deep containment pit

Copyright © 2019 by NCEES 57 NEXT→

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL PRACTICE EXAM

69. Based on ISA symbology, match the symbol descriptions below to their corresponding
symbols.

Symbol Descriptions

pH Meter

Relief Valve

Temperature Controller

Pressure Controller

Rupture Disc

70. A food-processing plant is considering use of new gas-fired ovens with a total capital cost of
$900,000, a useful life of 5 years, and a salvage value of $100,000. Use a net cash flow of
$400,000/year for 5 years and a 7% discount rate. The net present value is most nearly:

o A. $1,640,000
o B. $811,000
o C. $787,000
o D. $740,000

Copyright © 2019 by NCEES 59 NEXT→

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL SOLUTIONS

69
 This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL SOLUTIONS

1. Since the heating value given is on a dry and ash-free basis, first calculate the amount of
organics in 1 lb of feed:

Without emulsifying agent: 1 lb − (15% × 1 lb) =

0.85 lb orimulsion
Amount of organics in orimulsion: 77%
0.85 lb × 0.77% =
0.655 lb
0.655 lb organics 16,800 Btu
Calculate heating value: × 10,996 Btu/lb feed
=
lb feed lb organics

THE CORRECT ANSWER IS: A

2. To calculate the flow rate of N2 (lb/hr), first calculate the flow rate of N2 (moles/hr) then
convert to mass:

Flow rate of N 2 : 100 lb moles/hr × 80 mol% =

80 lb moles N 2 /hr

Mass flow rate of N 2 : 80 lb moles/hr × 28 lb/lb moles =

2, 240 lb/hr

THE ACCEPTABLE RANGE IS: 2,230–2,250

3. Perform a mass balance around the reboiler:

L= V + B
Use B from table:
B = 1.259 lb mole/hr
Use L /V ratio:
L = 1.4 V
1.4 V= V + 1.259 lb mole/hr
1.259 lb mole/hr
=V = 3.15 lb mole/hr
0.4

THE CORRECT ANSWER IS: A

Copyright  2019 by NCEES 71

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL SOLUTIONS

20. Use the equilibrium relationship for the stoichiometric equation to determine  RSHg 4− 
 

K eq =
( RSHg 4− )( H + )

( Hg2+ )( RSH5− )
K eq ( Hg 2+ )( RSH5− ) (1012 )( 5 ×10−25 ) ( 0.01)
( RSHg )=
4−
= = 5 ×10−9 mol/L
( H+ ) (1×10−6 )
The total compensation of dissolved mercury is the sum of the concentrations of Hg 2+ and ( )
( RSHg4− ) .
( Hg2+ ) + ( RSHg4− ) = (5 ×10−25 ) + (5 ×10−9 ) ≅ 5 ×10−9 mol/L
THE CORRECT ANSWER IS: D

21. Eventually (as t → ∞), all of A would go to C. Similarly, any B formed would also revert to A
and form C.

B[t → ∞] = 0 g mol/L

THE CORRECT ANSWER IS: A

Copyright  2019 by NCEES 83

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL SOLUTIONS

57. The reboiler boilup ratio (V/B) is determined by an overall material balance and an ammonia
material balance. The feed (F) quantity is equal to the sum of the quantity of the bottoms B and
the quantity of the distillate D, i.e., F = B + D. The vapor flow (V) is equal to the distillate flow
D, i.e., V = D, since it is a stripping column (no reflux). Ammonia in the feed is equal to the sum
of the ammonia in D and B, or
0.4 F 0.95V + 0.01B
=
0.4( B + V=
) 0.95V + 0.01B
0.39 B = 0.55V
=V/B 0.39
= / 0.55 0.71

THE CORRECT ANSWER IS: C

58. The feed is a vapor with a composition of 0.013 and should be fed to the column as near this
composition as possible. Stage 6 has a vapor from it of 0.0337, and Stage 5 has a vapor leaving it
of 0.0111. Thus the vapor feed should be to Stage 5 or above Stage 6.

THE CORRECT ANSWER IS: C

59. Given:
Vapor from the bottom tray, y1 0.70
Vapor from the reboiler, yB 0.75
Liquid from the bottom tray, x1 0.90
Bottom product, xB 0.95

Evaluate the L/V ratio in the stripping section of a column given compositional data at the
bottom tray and the kettle reboiler. The stripping section operating line starts at yB = xB = 0.95.
Thus, the following is obtained:
L= V + B
B= L − V
L × x1 =V × yB + B × xB =V × yB + ( L − V ) xB =V × yB + L × xB − V × xB
L( x1 − xB )= V ( yB − xB )
L yB − xB 0.75 − 0.95 −0.20
= = = = 4.00
V x1 − xB 0.90 − 0.95 −0.05

THE CORRECT ANSWER IS: B

Copyright  2019 by NCEES 112

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL SOLUTIONS

62. The combined organic and aqueous distillate composition is shown on the diagram in the two-
phase region. The organic distillate product composition is located on the solubility curve, but
it is not on the operating line. The point on the diagram for the aqueous phase composition
must be:
• On the solubility curve
• On the opposite side of the plait point for the point representing the organic distillate
product
• On the opposite side of the operating line for the point representing the organic distillate
product
• On a line connecting the point representing the organic distillate product and the point
representing the combined distillate product

THE CORRECT ANSWER IS MARKED WITH AN ×.

Copyright  2019 by NCEES 115

This is a preview. Some pages have been omitted. Copyrighted by NCEES. For permission to reuse, email permissions@ncees.org.

PE CHEMICAL SOLUTIONS

69. The ANSI/ISA standard S5.1-1984 (R1992) Instrumentation Symbols and Identification defines
how each symbol is constructed using graphical elements, alpha and numeric identification
codes, abbreviations, function blocks, and connecting lines. A minimally competent engineer
should be familiar with these standard instrumentation symbols and identification. In this
standard, P in the first position denotes pressure. As the determination of pH requires an
analysis, the letter A in the first position is proper. The letter E in the second position denotes
"sensor" (primary element), but the question calls for local display. Therefore, the second letter
should be I, which stands for "indication" when used in the second position.

THE CORRECTLY LABELED SYMBOLS ARE:

Pressure Controller

Temperature Controller

pH Meter

Rupture Disc

Relief Valve

Copyright  2019 by NCEES 120