MIXED

Question 1

How many degrees of freedom are allowed for a substance at its triple point?
3
1
0
2

Answer 1

0

Question 2

An unsteady-state operation is one in which the rate of accumulation is
zero
constant
positive
negative

Answer 2

constant

Question 3

What does the dew point temperature of the ambient air tell us?
It is an indication of the amount of water vapor in the air.
It indicates the lowest temperature of the day.
It tells us how hot it will be in the next few hours.
It indicates the highest temperature of the day.

Answer 3

It is an indication of the amount of water vapor in
the air.

Question 4

Within a splitting point in a non-reactive process, which of the following balances will not yield any useful
information?
overall mass balance
energy balance
component balance
none of the choices

Answer 4

component balance

Question 5

A chemical reaction has the following thermodynamic data: positive enthalpy change, positive entropy change, and
negative Gibbs free energy change. What can we deduce from these information?
The reaction is exothermic and spontaneous.
The reaction is endothermic and non-spontaneous.
The reaction is endothermic and spontaneous.
The reaction is exothermic and non-spontaneous.

Answer 5

The reaction is endothermic and spontaneous.

Question 6

A Carnot refrigerator is operating between high and low reservoir temperatures of TH and TL, respectively. Which
of the following changes will greatly increase the coefficient of performance of the Carnot refrigerator?
increase TH while keeping TL constant
decrease TH while keeping TL constant
decrease TL while keeping TH constant
The COP is not dependent on TH and TL

Answer 6

decrease TH while keeping TL constant

Question 7

The condenser of a steam power plant receives mixed saturated steam at a temperature and pressure of TS and PS,
with X% vapor. The outlet stream is pure saturated liquid at the same pressure. Which of the following conditions
will yield the lowest amount of heat that needs to be removed by the condenser?
X approaches 0
X = 1
X approaches 1
X = 0.5

Answer 7

X approaches 0

Question 8

Which of the following is a correct collection of units for thermal resistance?
°𝑅 ∙ ℎ^−1 ∙ BTU
°𝑅^−1 ∙ ℎ ∙ BTU^−1
°𝑅 ∙ ℎ ∙ BTU^−1
°𝑅 ∙ ℎ^−1 ∙ BTU^−1

Answer 8

°𝑅 ∙ ℎ ∙ BTU^−1

Question 9

This type of fluid displays an increase in viscosity as the rate of shear strain is increased, regardless of time frames.
thixotropic
dilatant
rheopectic
pseudoplastic

Answer 9

dilatant

Question 10

For laminar flow inside a pipe, the average and maximum fluid velocities inside are related as 𝑢ave/𝑢max = 0.5. What happens to this ratio as the flow becomes more turbulent?
𝑢ave/𝑢max remains at 0.5
𝑢ave/𝑢max approaches 0
𝑢ave/𝑢max exponentially increases
𝑢ave/𝑢max approaches 1

Answer 10

𝑢ave/𝑢max approaches 1

Question 11

This dimensionless number is useful in calculations involving free convection where buoyancy forces dominantly
drive fluid motion.
Ra
Re
Gz
Nu

Answer 11

Ra

Question 12

For an incompressible Newtonian fluid in laminar, steady, and fully-developed flow inside a uniform horizontal pipe of diameter D and length L, how will the pressure drop change if the fluid velocity is doubled while all other parameters are kept constant?
∆𝑃 will decrease to a fourth of the original
∆𝑃 will be halved
∆𝑃 will quadruple
∆𝑃 will be doubled

Answer 12

∆𝑃 will be doubled

Question 13

What is the hydraulic diameter of a pipe with square cross section, side length of s?
s^2
4s
s
s/2

Answer 13

s

Question 14

For a fluid flowing inside pipe at a constant Reynolds number, how will the Fanning friction factor change when
changing from a smooth to a rough pipe?
f will decrease
f will increase
f approaches 0
f approaches 1

Answer 14

f will increase

Question 15

What is the head loss experienced by a fluid when flowing from a large tank to the entrance of a pipe with a sharp edge?
(𝑢^2)/(2𝑔𝑐)
0.5
0.5(𝑢^2)/(2𝑔𝑐)
0.5(𝑢^2)/(2𝑔)

Answer 15

0.5(𝑢^2)/(2𝑔)

Question 16

A certain centrifugal pump can generate a head of H for a discharge of Q. If two of such pumps are connected in
series, what would be the new discharge developed by the system?
Q
2Q
Q/2
Q^(1/2)

Answer 16

Q

Question 17

In particle size reduction, energy laws are often used as a starting point to estimate the energy required for
comminution. Which of the following energy laws assumes that the energy consumption is proportional to the new
surface area produced by size reduction?
Kick’s law
Bond’s law
Rittinger’s law
none of the choices

Answer 17

Rittinger’s law

Question 18

Which dimensionless number is used for determining the ideal power consumption of agitators?
Po
Ra
Ar
Nu

Answer 18

Po

Question 19

Centrifuge X has a basket height of B and radius of R, operated at a rotational speed of N. If the larger centrifuge
Y (double the radius of X but same height) is used at the same rotational speed for the same slurry, what will be
relationship between their output capacities?
QY = 2QX
QY = QX
QY = QX/2
QY = 4QX

Answer 19

QY = 4QX

Question 20

For a binary mixture of non-polar gases, how does the mass diffusivity change if the absolute temperature is doubled at constant pressure?
increase by a factor of 2^(3/2)
decrease by a factor of 2^(3/2)
increase by a factor of 2
decrease by a factor of 2

Answer 20

increase by a factor of 2^(3/2)

Question 21

The drag coefficient of a rigid spherical particle generally decreases linearly with increasing Reynolds number for:
Re = 1
Re < 0.1
Re < 10,000
Re > 10

Answer 21

Re < 0.1

Question 22

Which factor leads to the decrease in average settling velocity of particles in hindered conditions, compared to free settling?
increased fluid viscosity
less gravitational pull on particles
increased fluid density
interactions between particles

Answer 22

interactions between particles

Question 23

10. A single-effect evaporator has feed temperature of TF, product temperature of TL, vapor temperature Tv, and steam temperature Ts. At steady-state, what is the driving force to evaporation?

Answer 23

TS-TL

Question 24

What is the driving force to crystallization?

Answer 24

supersaturation

Question 25

A wet solid initially contains x1% free moisture, above the critical moisture content, and it is subjected to a stream of hot air flowing at a volumetric flow rate of Q and inlet conditions of T, and RH. Which of the following steps will accelerate the rate of drying?
decrease T
increase Q
increase RH1
decrease Q

Answer 25

increase Q

Question 26

Which of the following is true for a binary system with a relative volatility of 1?
a longer distillation time is required for separation
more stages must be provided to achieve substantial separation
distillation can perfectly separate the two components
no separation can occur via distillation

Answer 26

no separation can occur via distillation

Question 27

What happens to the operating line of an absorption column as we increase the mass flow rate of the absorbent?

Answer 27

the operating line approaches verticality

Question 28

Which of the following is not a desirable quality of a solvent in liquid-liquid extraction?
low viscosity
readily available
density close to that of water
high selectivity

Answer 28

density close to that of water