Thermodynamics (PHYS2140)
BSc, Physics - PHYS
Semester: First Semester
Level: 200
Year: 2016
THE UNIVERSITY OF BAMENDA
FACULTY OF SCIENCE DEPARTMENT OF PHYSICS
Thermodynamics: PHYS2140 Tutorial Sheet I
Continuous Assessment 2016/2017
Physics Year 1 Duration: 2h
Exercise 1:
(3marks)
The experiments have shown that, the isobaric thermal expansion coefficient a and the
isothermal compression coefficient of one mole of a gas, is expressed in term of independent
variables p and T. it is written by the equations: a =
and = =
()
Where where R and b are constants. Find the equation of state of this gas, relative to one mole.
Exercise 2:
(5marks)
1. Represent the isotherms of van der Waals gases in the p-V diagram
2. Write the van der Waals state equation, give the conditions of idealizing this state
3. Expand the product
pv
in Taylor series with respect to v in the form
=
1 +
+
+ ⋯
,
where
A
and
B
should be determined.
Exercise 3:
(7marks)
A
closed, rigid container of volume 0.5 m
3
is placed on a hot plate. Initially, the container holds a two-phase
mixture of saturated liquid water and saturated water vapor at
Pi=
1.5bar. with a quality of 0.5. After
heating, the pressure in the container is
P2
-
1.5bar.
(use data in the table)
1. Indicate the initial and final states on a
T--v
diagram
2. Determine the temperature, in °C, at each state.
3. Determine the mass of vapor present at each state, in kg.
4. If heating continued, determine the pressure, in bar, when the container holds only saturated vapor.
Exercise 4:
(5 marks)
The state equation o f a real gas is written
+
√
(v-b) = RT, where R = 8.3J/mol.
o
K,a
=41.4P a.
o
K.m
6
/molSI and b = 3.3 X 10
-5
m
3
/mol. The molar specific heat at constant volume
is equal to Cv =
R whatever the temperature when its pressure tends to zero.
www.schoolfaqs.net
1. Write the elementary heat in term of C
v
and
l
coefficients.
2. Establish the relations
l = T
and
= T
starting by the fact that dU and dS are total.
Calculate the value of
C„
at temperature
T,
when the molar volume of gas is held to be v.
3. Calculate the variation AC„ when the molar volume passes from v
0
to 3v0 at constant temperature.
v
o
= 20 liters, T= 300°K.
4. Calculate the varaiation Cv, when the molar volume passes from v
o
to 3v
o
at constant temperature
v
0
= 20 liters, T = 300
o
K
www.schoolfaqs.net
www.schoolfaqs.net
