Title: Laws of Thermodynamics 1
1Laws ofThermodynamics 1
- Disusun Oleh
- Ichwan Aryono, S.Pd.
2First law of thermodynamics
First Law of thermodynamics states that
Whenever heat Q is given to a system, a portion
of heat is used to increase its internal energy
in the amount of DU, whereas the remaining leaves
the system when the system performs a work W to
its surroundings. Mathematically, the first law
of thermodynamics is formulated by Q DU W
Qgt0
W positip jika sistem melakukan usaha W negatip
jika sistem dikenai usaha Q positip Jika sistem
menerima kalor Q negatip jika sistem melepas
kalor Energi dalam DU tidak terpengaruh oleh
proses, yang dilihat adalah hanya pada keadaan
awal dan keadaan akhir
Wgt0
Wlt0
Qlt0
3The first law of thermodynamics for isothermal
process
At isothermal Process DT 0, so DU 0 The
work done by the isothermal process is
so Q DU W 0 W W Q
4The first law of thermodynamics for
isobaricprocess
At isobaric process the pressure is constant DP
0 Internal energy , so
5The first law of thermodynamics for isochoric
process
At Isochoric process volume is constant, DV 0,
so the work done W PDV 0, its produce
6The first law of thermodynamics for adiabatic
process
Adiabatic process is a process without any
transfer of heat into or from the system (Q0)and
it applies
7Student Activity 1
A system absorbs 1500 J of heat from surrounding
and does work done 2200 J . Determine the
change of internal energy system, increases or
decreases ?
8Student Activity 2
System absorbs 1500 J of energy from surrounding.
At the same time 2200 J work done is given to the
system. Determine the change of internal energy
of the system. Is temperature decreses or
increases ?
9Student Activity 3
Two mol of ideal gas is expans from point I to
point F with three difference way as shown in
diagram below. Calculate the work done, change of
internal energy, and calor in each way IAF, IF
and IBF, state in joule
P(atm)
A
4
I
B
F
1
V(L)
2
4
10Student Activity
P(Pa)
Four mol of ideal gas in cylinder container
change its conditional as shown in graphic P-V
beside. Determine the work done, internal energy
and calor if the gas is change from A to C thrue
(a) ABC, (b) AC
A
B
500
C
200
V(cm3)
0
800
500
300
11Student Activity 5
- Three different processes act on system.
- In process A, 42J of work are done on the system
and 77J of heat are added to the system. Find the
change in the systems internal energy. - b. In process B. the system does 42 J of work
and 77J of heat are added to the system. What is
the change in the systems internal energy ? - c. In process C, the systems internal energy
decreases by 120 J while the system performs 120
J of work on its surroundings. How much heat was
added to the system ?
12Student Activity 6
An ideal gas is taken through the four processes
shown in figure below. The changes in internal
energy for three of these processes are as
follows DUAB 82 J, DUBC 15 J, DUDA -56
J. Find the change in internal energy for the
process from C to D
D
C
pressure
A
B
volume
13Student Activity 7
a. Find the work done by a monoatomic ideal gas
as it expands from point A to point C along the
path shown in figure below. b. If the temperature
of the gas is 220K at point A, what is its
temperature at point C ? c. How much heat has
been added to or removed from the gas during this
process ?
B
600
400
Pressure P(kPa)
A
C
200
Volume, V(m3)
0
2
4
6
8
10
14Student Activity 8
- During an adiabatic process, the temperature of
3.52 moles of monoatomic ideal gas drops from
485oC to 205oC. For this gas, find - The work it does
- The heat it exchanges with its surroundings, and
- The changes in internal energy
15Student Activity 9
- An ideal gas follows the three-part process shown
in figure below. At the completion of one full
cycle, find - The net work done by the system
- The net change in internal energy of the system
- The net heat absorbed by the system
A
150
Pressure P(kPa)
100
B
50
C
1
2
0
3
4
Volume, V(m3)
16Quiz
- Suppose 57.5 moles of an ideal monoatomic gas
undergoes the series of processes shown in figure
below. - Calculate the temperature at the points A, B, and
C. - For each process, A-B, B-C, and C-A, state
whether heat enters or leaves the system, Explain
in each case. - Calculate the heat exchanged with the gas during
each of three process.
A
150
Pressure P(kPa)
100
B
50
C
1
2
0
3
4
Volume, V(m3)