GROUP 5

Hanafi Idham Kholid (11307141012) and etc

2nd assignment of physical chemistry IILecturer : Jashlin Ikhsan

1. What is actually kinetic theory of Gas? (Apa sebenarnya teori kinetik gas?)The kinetic theory of gases is a law that explains the behavior of a hypothetical ideal gas. According to this theory, gases are made up of tiny particles in random, straight line motion. They move rapidly and continuously and make collisions with each other and the walls. This was the first theory to describe gas pressure in terms of collisions with the walls of the container, rather than from static forces that push the molecules apart. Kinetic theory also explains how the different sizes of the particles in a gas can give them different, individual speeds.

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2. Do all gases move with the same speed? (Apakah semua gas bergerak dengan kecepatan yang sama?)No, gas molecules move at different speeds, colliding fast molecules with slow molecules would transfer energy from the fast molecules to the slow molecules, making the slow molecule faster than it was going before.

3. Does a gas move with the stable speed during its movement?( Apakah gas bergerak dengan kecepatan stabil selama gerakannya?)No, because the velocity of the gas molecules will change the collision as well as the gas velocity is affected by temperature

4. If 1 L gas contains 4 kinds of molecules with kinetic energy of each of molecule is 3, 6, 10, and 2 Joule, respectively. How many Joule is the total energy of the system based on the kinetic theory of gas? (Jika 1 L gas berisi 4 jenis molekul dengan energi kinetik dari masing-masing molekul adalah 3, 6, 10, dan 2 Joule, masing-masing. Berapa banyak Joule adalah energi total sistem berdasarkan teori kinetik gas)Based on Kinetic theory of gases, we know that the total kinetic energy comes from the energy of gas molecules. Then, we can calculate the total kinetic energy

∑ Ek=Ek1+Ek2+Ek3+Ek4

¿ (3+6+10+2 ) Joule

¿21Joule

5. Using Maxwell-Boltzman distribution, determine the equation of most probable speed of gases! (Menggunakan distribusi Maxwell-Boltzman, tentukan persamaan yang paling mungkin kecepatan gas)The most probable speed,V pb , is the speed most likely to be possessed by any molecule (of the same mass m) in the system and corresponds to the maximum value or mode of dNThe Boltzmann distribution is given (Look at below)

dNN

=4π ( m2πkT )

32 e−mc

2 /2kT c2dc

dNNdc

=4 π ( m2 πkT )

32 e−mc

2/2kT c2

Lower to c, then the value of the first derivative = 0 ( y’=0 ) (Turunkan terhadap c,

kemudian nilai turunan pertamannya = 0)

ϑϑc (

dNNdc )=c e−mc

2/2kT(2−mc2

kT )=0

(2−mc2

kT )=0

Then,

V pb=cpb=√ 2kTm

=√ 2RTM

Where R is the gas constant and M = NA. m is the molar mass of the substance

6. Calculate the ratio of root mean square speed, average speed, and most probable speed of gases! (Hitung rasio Vrms, VaveragedanVmost possible)

V rms :V average:V mp

√ 3 RTM

:√ 8 RTπM

:√ 2RTM

√3√ RTM : √ 8π √ RTM :√2√ RTM√3 :√ 8

3,14:√2

√3 :√2,55 : √21,73 :1,59 :1,41

1,23 :1,13 :1