Midterm 1 solutions
1. (3 points) It is possible to calculate the absolute entropy of a pure substance (T/F).
_T_ - See the Third Law the absolute entropy is zero for all perfect crystalline
substances at absolute zero
2. (3 points) The thermal efficiency
Chemical Engineering 141
Spring 2014
Homework 4
Due Friday March 7th
Please turn in your solution to each problem on separate sheets of paper. Write your name
on all sheets. Show all work
Problem 1
Very pure liquid water can be subcooled at atmospheric pr
Chemical Engineering 141
Spring 2014
Due Friday, April 4th
Homework 7
Please turn in your solution to each problem separately. Write your name on all sheets. Show all
work.
Problem 1
Assuming the validity of Raoults law, do the following calculations for
Chemical Engineering 141
Spring 2014
Homework 3
Due Friday February 21st
Please turn in your solution to each problem on separate sheets of paper. Write your name
on all sheets. Show all work
Problem 1
A Carnot engine operates between two finite heat rese
Chemical Engineering 141
Spring 2014
Homework 8
Due Friday, April 18th
Please turn in your solution to each problem separately. Write your name on all sheets. Show all
work.
Problem 1
Ten (10) kmol hr-1 of hydrogen sulfide gas is burned with the stoichiom
Chemical Engineering 141
Spring 2014
Homework 6
Due Friday, March 21st
Please turn in your solution to each problem separately. Write your name on all sheets. Show all
work.
Problem 1
A furnace fails in a home in the winter, but the electric power remains
Chemical Engineering 141 Spring 2014
Homework 1
Due Friday, February 7
Please turn in your solution to each problem on separate sheets of paper. Show all work.
Problem 1
A closed system contains an ideal gas at 20C and 1 bar with an initial molar volume 0
Chemical Engineering 141
Spring 2014
Due Friday, May 2nd
Homework 10
Please turn in your solution to each problem separately. Write your name on all sheets. Show all
work.
Problem 1
A system initially containing 2 mol C2H4 and 3 mol O2 undergoes the react
Chemical Engineering 141 Spring 2014
Homework 2
Due Friday, February 14
Please turn in your solution to each problem (except problem 1 and 2) on separate sheets of
paper. Please put problem 1 and 2 together on the same sheet. Show all work.
Problem 1
Prob
2.26
Fifty kmol per hour of air is compressed from P1 = 1.2 bar to P2 = 6.0 bar in a steady-flow
compressor. Delivered mechanical power is 98.8 kW. Temperatures and velocities are:
T1 = 300 K
u1 = 10 m s-1
T2 = 520 K
u2 = 3.5 m s-1
7
Estimate the rate of
Name:
SID:
Chemical Engineering 141: Thermodynamics
Spring 2014
Monday, April 7th, 2014
Midterm 1 50 minutes 100 points total
Turn in equation sheet with exam
Part I: Concept Questions
1. (1 point) For the same compression ratio, the Diesel engine has a h
Problem 2
Operating data are taken on an air turbine. For a particular run, P 1 = 8 bar, T1 = 600 K, and P2 =
1.2 bar. However, the recorded outlet temperature is only partially legible; it could be T 2 = 318,
348, or 398K. Which must it be? For the given
Problem 1
Problem 2
Problem 4
Looking up values for A, B, C, D for O2, CO2, H2O, and N2 gives
n
O2 (3)
CO2 (4)
H20 (5)
N2 (6)
A
1.025
1.05
2
11.618
nA
B
3.639 3.729975
5.457 5.72985
3.47
6.94
3.28 38.10704
nB
D
nD
0.506 0.51865
-0.227 -0.23268
1.045 1.097
Problem 1
A small adiabatic air compressor is used to pump air into a 20-m3 insulated tank. The tank
initially contains air at 25C and 101.33 kPa, exactly the conditions at which air enters the
compressor. The pumping process continues until the pressure
Chemical Engineering 141
Spring 2014
Homework 11
Practice Assignment
This assignment is for individual practice and will not be graded.
Problem 1
In chemical-reaction engineering special measures of product distribution are sometimes used
when multiple re