ChE226 Thermodynamics I
1st midterm exam 03/09/2016
Student Name:
Student ID:
1"
"
1. Conceptual questions
(I) A gas undergoes reversible expansion from 40 bar and 400 K to 1 bar and 400 K by the two
different pathways.
A. A constant pressure process to t
2nd midterm exam 04/13/2016
ChE226 Thermodynamics I
1. In a steady state combustion experiment, hydrocarbon gas and oxygen flow into an adiabatic
burner and various reaction products flow out. (30 points)
(a) Write the first law energy balance for the pro
ChE 226 2016
Chapter 4
Heat Effect, Part 1: Sensible Heat and latent Heat
Overview:
Sensible heat effects(changing the temperature of a substance)
o
Computing changes in internal energy using Cv:
2
=
o
1
Computing changes in enthalpy Cp:
2
=
1
o Eval
Additional practice problems for Chapter 6
1. A Hilsch vortex tube operates with no moving mechanical parts, and splits a gas stream into
two streams: one warmer and the other cooler than the entering stream. One such tube is reported
to operate with air
ChE 226 Homework Assignment 8
Due Friday (April 21)
TA office hours: Thursday (April 20) from 7:00 to 8:00 (CRIB)
TA: Eric Ying ([email protected])
1. A steam turbine operates adiabatically with a stream rate of 25 kg/s. The steam is
supplied at 1300 kPa an
ChE 226 Home Work Assignment 5
TA: Zoey Meng ([email protected]), Due Wednesday (March 22th)
1. (20 points) Calculate the heat required to raise the temperature of 1.5 mol of benzene
from 300oC to 700oC in a steady-flow process at a pressure suf
Second Midterm Exam
ChE 231
Spring 2016
Problem 1 (20 pts). Consider the system of linear algebraic equations Ax = b where:
2 4 1
1
A = 1 1 1 , b = 2
1 4 0
3
1. (15 pts) Perform Gauss-Jordan elimination to calculate A1 . Show all steps.
2. (5 pts) Use A1
1. Given that the vapor pressure of n-butane at 350K is 9.4573 bar, find the molar volume of (a)
Saturated-vapor and (b) saturated-liquid n-butane at these conditions as given by the RK equation.
From Appendix Table B1, we will know critical temperature a
ChE 226 Home Work Assignment 3
Due Wednesday (February 22)
TA: Helen Hua ([email protected])
1. An ideal gas initially at 600 K and 10 bar undergoes a four-step mechanically reversible cycle
in a closed system. In step 12, pressure decreases isothermally to
8.1. The Steam Power Plant
295
from Heat
-r_-hhlr-_n
294 CHAPTER 8. Production of Power
nd4 -> i. The lines are no
he exhaust is normally
erosion problems are
the effect is
Thus by Eq. (8.2) applied to the condenser
illustrates the effects of
on of increa
ChE 226
Chapter 3
Volumetric Properties of Pure Fluids Part I
Overview:
Equation of state: what they are and why we need them
Definitions and use of volume expansivity and isothermal compressibility
Properties of ideal gases
Process calculations with idea
ChE 226 Home Work Assignment 6
Due Wednesday (March 29th)
TA: Sanket Sabnis ([email protected]);
1. An engineer claims to have designed a practical heat engine that has an efficiency of 0.35
using heat reservoirs with temperature of 200oC and 25oC. Is thi
ChE 226 Home Work Assignment 7
Due Wednesday (April 5)
TA: Helen Hua ([email protected])
1. Two mole of ideal gas, is compressed adiabatically in a piston/cylinder device from 2 bar and
25oC to 7 bar. The process is irreversible and requires 25% more work th
ChE 226 Homework Assignment 9
TA: Zoey Meng ([email protected]), Due Friday (April 28th)
1. Saturated steam at 125 kPa is compressed adiabatically in a centrifugal compressor to 700 kPa
at the rate of 2.5 kg/s. The compressor efficiency is 78%.
Example 7.6
A steam turbine with rated capacity of 56400 kW (560400 kJ/s) operates with steam at inlet conditions
of 8600 kPa and 500oC, and discharges into a condenser at a pressure of 10 kPa. Assuming a turbine
efficiency of 0.75, determine the state of
Esys + Esurr = 0
General
Energy Balance
Closed System: no mass flow
across boundaries
Ut = Q + W, if Ek = Ep = 0
Esys = Q + W
Homogenous with n moles
material
nU = Q + W
Homogenous for 1 mol
U = Q + W
Mechanically Reversible
W = -PVtot = -P(nV)
Isochoric;
ChE226
Chapter 2
The First Law and other Basic Concepts (Chapter 2 in SVA
Overview:
Definition of internal energy
The first law : Energy is conserved
Energy balances for closed systems
State variables and the concept of thermodynamic states
The Gibbs phas
Solution - ChE 226 Homework Assignment
1. Reported values for the Virial coefficients of methane vapor at 200 o C are B = -4.19*10-6
m3/mol; C = 1.615*10-9 m6/mol2
Calculate specific, V, and, compressibility factor, Z, for methane at 200 o C for 20 bar by
ChE 226 Home Work Assignment 5
TA: Zoey Meng ([email protected]), Due Wednesday (March 22th)
1. (20 points) Calculate the heat required to raise the temperature of 1.5 mol of benzene
from 300oC to 700oC in a steady-flow process at a pressure suf
Date
Topic
M 1/23 Chapter 1-Introduction
W 1/25 Chapter 1-Introduction
F 1/27 Chapter 1-Introduction
M 1/30 Chapter 2- First Law
W 2/01 Chapter 2- First Law
F 2/03 Chapter 2- First Law
Discussion Session
M 2/6 Chapter 2- First Law
W 2/8 Chapter 2- First L
ChE 226 Homework Assignment 9
TA: Zoey Meng ([email protected]), Due Friday (April 28th)
1. Saturated steam at 125 kPa is compressed adiabatically in a centrifugal compressor to 700 kPa
at the rate of 2.5 kg/s. The compressor efficiency is 78%.
ChE 226
Chapter 5B
The Second Law of Thermodynamics, part 2:
Overview:
The second law of thermodynamics can be stated mathematically as 0 for all
processes
Applications of the second law
o Entropy balances
o Ideal work
o Thermodynamic efficiency
o Lost wo
Appendix F
Steam Tables
F.l INTERPOLATION
When a value is required from a table at conditions which lie between listed values. interpo-
lation is necessary. If M, the quantity sought, is a function of a single independent variable
X and if linear interp
Chapter 3
PVT behavior of pure fluids
PV=RT
good for low P
U depends only on T, (not P), thus Cv = Cp
Ideal-gas
Ideal Gas
For an ideal gas undergoing any process:
! = T1T2 "#$%
& = T1T2 "'$%
For an ideal gas in a closed system undergoing a mechanically
For process of: No rxn, No comp , No phase : Qin -> T
1. V = 0 or IG/IL -> U = CvT, if rev-> Q = CvT
2. P = 0 or IG -> H = CpT, if rev-> Q = CpT
CvIG = CpIG R
CpIGmixture = yA*CpIGA + yB*CpIGB +
CpIGdT = <CpIG>H(T-T0)
<Cp>H = R*[A + B(T+T0)/2 + C(T2+T*T0
ChE 226 Home Work Assignment 7
Due Wednesday (April 5)
TA: Helen Hua ([email protected])
1. Two mole of ideal gas, is compressed adiabatically in a piston/cylinder device from 2 bar and
25oC to 7 bar. The process is irreversible and requires 25% more work th
Additional practice problems for Chapter 6
1. A Hilsch vortex tube operates with no moving mechanical parts, and splits a gas stream into
two streams: one warmer and the other cooler than the entering stream. One such tube is reported
to operate with air