Penentuan Rasio Panas Jenis (Cp/Cv) untuk Gas N2 dan H2
ｧＧｾ＠
KETEKNIKAN PERTANIAN
PENENTUAN RASIO PANAS JENIS (C/Cv)
UNTUK GAS N2 DAN H2
Determination Of Specific Heat Capacity Ratio (Cv/Cp) of Gas N2 And H2
Wiludjeng Trisasiwi\ Dyah Wulandani l , Kamaruddin Abdullah 2 dan'
Armansyah H. Tambunan 2
ABSTRACT
The ratio of specific heat capacity, at constant pressure to that at constant
volume (clc,), of a gas can be determined by either the adiabatic expansion
method or the sound velocity method The objective of this experiment is apply the
adiabatic expansion method for determining the specific heat capacity ratio of gas
N z and O2. The result showed that the ratio were 1.14 and 1.19 respectively for gas
N z and O2. The value obtained by the experiment was different about 15 to 19%
from the result determined by theoretical method using 5 degree of freedom.
Theoretically clc" of both gas N2 and O2 which have 5 degree offreedom are 104.
The difference was considered to be caused by the experimental condition, which
were not sufficiently adiabatic, as required by the method However, the
simplicity of the method and clarity of its theoretical approach is advantageous to
be used by students ofAdvance Thermodynamic class as a practical exercise.
KeyWords: specific heat capacity ratio (Cp/Cv), adiabatic expansion method
PENDAHULUAN
LataT Belakang
.
.' Qaripcill;SiJrpriQsip termodinamika secara umUrn, bisa ditl,ll1W1kan
hubungan antar kuantitas misalnya
koefisien . ekspansi, kompresibilitas,
.panas jenis, transformasi panas dan
koefisien dielektrik, terutama sifat-sifat
ｹｾｮｧ＠
dipengaruhi temperatur.
Panas jenisgas dapat dihitung
dengan menggunakan .. te.ori kinetik
. berbasis pada model molekuler .
met.ode kecepatan
. .ｐｾｊｬ･ｮｴｵ｡､ｧ＠
Sqa.{a telah menunjukkan. hasil yang
I
2
sarna dengan teori. .Pada penelitian ini
ingin dibuktikan bahwa dengan metode'
. ekspansi
adiabatik,
dapat
pula
digunakan untuk menentukan . rasio
panas jenis.
Penelitian mengenai panas
jenis gas belum banyak dilakukan,
ｫ｡ｲ･ｾ＠
keterbatasan alat.
Dengan
metode ekspansi adiabatik menggunakan peralatan yang sederhana dan
beberapapenyempurnaan diharapkan
instrumen
dapat digun*an .ｳｾｧ｡ｩ＠
ukur rasio panas jenis gas yang baik : .
Mahasiswa Program Pasca Sarjana Institut Pertanian Bogor
StafPengajur • JurusanTEP, FATETA Institut Pertanian Bogor
39
KETEKNIKAN PERTANIAN
PENENTUAN RASIO PANAS JENIS (C/Cv)
UNTUK GAS N2 DAN H2
Determination Of Specific Heat Capacity Ratio (Cv/Cp) of Gas N2 And H2
Wiludjeng Trisasiwi\ Dyah Wulandani l , Kamaruddin Abdullah 2 dan'
Armansyah H. Tambunan 2
ABSTRACT
The ratio of specific heat capacity, at constant pressure to that at constant
volume (clc,), of a gas can be determined by either the adiabatic expansion
method or the sound velocity method The objective of this experiment is apply the
adiabatic expansion method for determining the specific heat capacity ratio of gas
N z and O2. The result showed that the ratio were 1.14 and 1.19 respectively for gas
N z and O2. The value obtained by the experiment was different about 15 to 19%
from the result determined by theoretical method using 5 degree of freedom.
Theoretically clc" of both gas N2 and O2 which have 5 degree offreedom are 104.
The difference was considered to be caused by the experimental condition, which
were not sufficiently adiabatic, as required by the method However, the
simplicity of the method and clarity of its theoretical approach is advantageous to
be used by students ofAdvance Thermodynamic class as a practical exercise.
KeyWords: specific heat capacity ratio (Cp/Cv), adiabatic expansion method
PENDAHULUAN
LataT Belakang
.
.' Qaripcill;SiJrpriQsip termodinamika secara umUrn, bisa ditl,ll1W1kan
hubungan antar kuantitas misalnya
koefisien . ekspansi, kompresibilitas,
.panas jenis, transformasi panas dan
koefisien dielektrik, terutama sifat-sifat
ｹｾｮｧ＠
dipengaruhi temperatur.
Panas jenisgas dapat dihitung
dengan menggunakan .. te.ori kinetik
. berbasis pada model molekuler .
met.ode kecepatan
. .ｐｾｊｬ･ｮｴｵ｡､ｧ＠
Sqa.{a telah menunjukkan. hasil yang
I
2
sarna dengan teori. .Pada penelitian ini
ingin dibuktikan bahwa dengan metode'
. ekspansi
adiabatik,
dapat
pula
digunakan untuk menentukan . rasio
panas jenis.
Penelitian mengenai panas
jenis gas belum banyak dilakukan,
ｫ｡ｲ･ｾ＠
keterbatasan alat.
Dengan
metode ekspansi adiabatik menggunakan peralatan yang sederhana dan
beberapapenyempurnaan diharapkan
instrumen
dapat digun*an .ｳｾｧ｡ｩ＠
ukur rasio panas jenis gas yang baik : .
Mahasiswa Program Pasca Sarjana Institut Pertanian Bogor
StafPengajur • JurusanTEP, FATETA Institut Pertanian Bogor
39