What is Chemical Engineering ?
You are majoring in Chemical Engineering and have been chosen to
return to your high school and recruit the best and the
brightest to follow in your footsteps. How would you explain
your newfound profession and convey an idea regarding the types of
tasks others may encounter in the ChE job market ?
 Explain the role of a ChE in "traditional" contexts [F: Ch
1]

 Define and give examples of a process (or ChE process)
 Identify tasks a ChE would perform in a given industry /
situation
 Explain the role of a ChE in emerging markets

 Distinguish between product and process design / analysis
 List the steps involved in product design
 Identify the tools used in process design / analysis

 Define the term balance equation and give examples of things
that might be balanced
 Describe the characteristics and purpose of a flowchart [F: Ch
4.3a]
 Identify a valid flowchart for a given process description
Engineering Calculations
In order to properly communicate with other engineers /
scientists you must use the correct language .How can you
use concise language to convey not only what you measured, but how
precise the measurement was ?
 Explain the utility of the proper use of units [F: Ch
2.12.4]

 Define and give examples of value, units, and dimensions in a
given expression
 Convert from one set of units to another
 Identify an invalid equation, based on dimensional
arguments
 Compare two quantities using a dimensionless group [F: Ch
2.6]
 Correctly use scientific notation [F: Ch 2.5]

 Write a value in scientific notation(using the correct number
of significant digits)
 Determine the number of significant digits both in a given
value as well as in the result of arithmetic
While measuring data is enormously useful you cannot possibly
measure every possible bit of information under every possible
condition(it would take too long and would be far too
expensive).How can you use limited data to obtain enough
information to get by ?
 Utilize curve  fitting or linear interpolation to estimate
unmeasured data from measured data [F: Ch 2.7]
 "Check" your results by order  of  magnitude estimation, back
substitution, etc.
Process and State Variables
Describing and analyzing processes requires that you can
understand, calculate, and manipulate both process data as well as
state variables.
How would you calculate process variable values from
measurements ?
 Manipulate process flow data [F: Ch 3.13.3]

 Interconvert mass, volume, and moles(and their flows)
 Calculate mass(mole) fractions from mole(mass) fractions for a
mixture
 Calculate pressures using a manometer(and explain the concept
of gauge pressure) [F: Ch 3.4]
 Interconvert between different temperature scales [F: Ch
3.5]
 Explain the difference between intensive and extensive
variables
Certain calculations require you to know quite a bit about the
"state" of a material(i.e., its state of aggregation(phase),
temperature, pressure, chemical composition, etc.).How can we
quantify properties about a material 's state?
 Calculate State Variables U and H [F: Ch 8.18.3b]

 Define "state variable"
 Explain why one must choose a reference point when calculating
state variables
 Generate "fictitious paths" from your reference state to your
desired state
 Use heat capacities and phase data to calculate H and U from
fictitious paths
 Use tabular data to determine U and H [F: Ch 7.5]
Balance and Process Fundamentals
Balances are simple accounting procedures used to aid in the
overall analysis of a process 's viability.
Exactly how ; a process is run, often determines much
regarding what the balance equations will look like.What are some
of the characteristics that a running process may have ?
 Characterize system operation [F: Ch 4.1]

 Give original examples of(and identify) batch, semi  batch,
continuous, steady, and transient processes
 Define open system, closed system, adiabatic, isothermal
What are quantities for which we can write balances ? Just like
a checkbook, we can have inputs / deposits / credits and we can
have outputs / withdrawals / debits.What are some of the
ways in which these ins and outs can occur ? What happens
if we put more in than we take out ?
 Explain the origin and physical meaning of each of the terms in
the General Mass Balance Equation [F: Ch 4.2]
 Write a General Energy Balance Equation [F: Ch 7.17.4]

 Explain the origin and physical meaning of each of the terms in
the General Energy Balance Equation
 Explain the difference between shaft work and flow work
 Simplify the appropriate form of the Energy Balance
Equation
Now that we have written our balance equations, how can we
concisely depict the information that we require to actually
do the balance (or show our results after we have
completed the balance) ?
 Draw and label a flowchart from a process description [F: Ch
4.3]
Performing Non  Reactive Mass and Energy Balances
Now that we know how to write the equations that will
get us started for balances, we need to worry about when
they are useful.How do we know when to write these equations, or
how many we need ?
 Perform single  unit mass balances [F: Ch 4.3]

 Perform a degree  of  freedom analysis for a single  unit
mass balance process
 Do the calculations suggested in the degree  of  freedom
analysis
Real processes often include more than one process
unit.How do we handle arbitrary numbers of units ? arbitrarily
complex arrangements of those units ?
 Identify relevant sub  systems within a multi  unit process
on which to perform a degree  of  freedom analysis(and
subsequently do the required calculations) [F: Ch 4.4]
 Perform mass balances(degree  of  freedom plus calculations)
for systems with recycle, bypass, and purge streams [F: Ch
4.5]
Energy balances can be used as an additional equation in mass
balances.
 Simplify and solve the General Energy Balance for non 
reactive systems [F: Ch 7.6]
Performing Reactive Mass and Energy Balances
When reactions occur, material balances become more difficult,
and energy balances are often more important.How do we handle
generation and consumption of molecular species ? What if we don
't even know the stoichiometry ?
 Calculate quantities necessary for reaction / chemistry
benchmarking

 Calculate the limiting reactant, excess reactants, percent
excess, and fractional conversion in a given reaction [F: 4.6]
 Define and calculate the yield and selectivity for reaction
networks [F: 4.6]
 Define and calculate the "atom economy" of a process
proposal
 Perform reactive mass balances(degree  of  freedom plus
calculations) [F: 4.7, 4.8]

 Write extent  of  reaction expressions from
stoichiometry
 Utilize equilibrium expressions to determine equilibrium
compositions and extents of reaction
 Perform atomic species balances
What effect do reactions have on energy balances ? How do we
handle fictitious paths of material that is generated or consumed
?
 Perform reactive energy balances [F: 9.13, 9.5]

 Explain how chemical reactions are handled in the General
Energy Balance
 Use Hess 's Law to determine the heat of reaction of given
reactions
Thermodynamics
Thermodynamics can be used to make the number of necessary
measurements smaller, or to make the type of measurement
easier.
It turns out that volumetric flowrates are far easier
to measure than mass or molar flows.How can we make use of this
information ?
 Use single  phase thermodynamics to convert from volumetric
flows to mass / molar flows [F: Ch. 5]

 Determine the density of a mixture of liquids
 Use the ideal gas law to determine P, V, or T of a single
component
 Determine the composition of a mixture of ideal gases from
their partial pressures or volume fractions
 Use one(or all) of the covered non  ideal equations(SRK,
compressibility factor, van der Waals, virial equation) to
determine P, V, or T
 Use equations of state for mixtures of gases
 Use equations of state in material balances
When multiple phases are in equilibrium with each
other, the problem becomes constrained .Can we use this
information, along with Thermodynamics, to further reduce the
number of necessary measurements ?
 Sketch a phase diagram and label relevant regions /
points(solid, liquid, gas, critical point, etc.) [F: 6.1]
 Use Gibbs phase rule to determine how much information is
necessary to specify the thermodynamic state of a system [F:
6.2]
 Explain the difference between the Gibbs phase rule and a
Degrees  of  freedom analysis
 Perform vapor  liquid equilibrium(VLE) calculations [F:
6.34]

 Estimate the vapor pressure of liquid components
 Use ideal solution expressions to determine the composition of
liquids and their corresponding vapors
 Define and use K values, Raoult 's law, and relative
volatility
 Distinguish between when Henry 's Law and Raoult' s Law would
be applicable
 Use Txy or Pxy diagrams for non  ideal(and ideal)
solutions
 Explain the relationship between y  x, Txy, and Hxy
diagrams
 Estimate the composition of liquids in equilibrium with solids
[F: 6.5]
 Estimate the composition of immiscible liquids in equilibrium
with each other(using either partition ratios or ternary phase
diagrams) [F: 6.6]
Performing Multi  Phase Mass and Energy Balances
Using thermodynamics in mass / energy balance problems means
that additional equations are available for solving the required
unknowns.
How can VLE calculations be used in mass balance
applications?
 Solve multi  component flash distillation problems

 Derive and use the lever  arm rule
 Explain and sketch the basic flash distillation process [W: Ch.
2.1]
 Derive and plot the operating equation for a binary flash
distillation on a y  x diagram [W: Ch. 2.4]
 Solve both sequential and simultaneous binary flash
distillation problems.
 Explain the difference between (and solve) binary and
multicomponent flash calculations [W: Ch. 2.5, 2.6]
 Write and solve mass and energy balances for multi  stage
distillation

 Explain the connection between column and flash distillation
processes [W: Ch. 3.1, 3.2]
 Write the mass and energy balances and equilibrium expressions
for any stage in a column [W: Ch. 3.4, 4.1, 4.2]
 Explain what constant molal overflow(CMO) is, and determine if
it is valid in a given situation [W: Ch. 4.2]
 Determine the operating equations for CMO systems [W: Ch.
4.3]
 Determine the number of stages required to achieve a
separation, using the Lewis method [W: Ch. 4.3]
 Calculate the feed quality and determine its effect on
flowrates [W: Ch. 4.4]
 Plot the feed line on a y  x diagram [W: Ch. 4.4]
 Determine the number of stages required to achieve a
separation, using the McCabe  Thiele method [W: Ch. 4.5]
 Solve total and minimum reflux problems when CMO is valid [W:
Ch. 4.5, 4.8, 4.10]
 Explain why multicomponent distillation is trial  and  error
[W: Ch. 5.1]
 Make appropriate assumptions and make external mass balances
for multicomponent distillation problems [W: Ch. 5.1]
 Perform gas  liquid(solubility) and liquid  liquid
equilibrium mass balances

 Explain what absorption and stripping do and describe a
complete gas treatment plant
 Use the McCabe  Thiele method to analyze absorption and
stripping systems for both concentrated and dilute systems
 Solve both immiscible and partially miscible extraction
problems