# Chapter 2 Gases¶

## Example 2.1 , Page no:21¶

In [1]:
import math
from __future__ import division

#initialisation of variables
P= 730 #mm
V= 20 #litres
T= -20 #C
P1= 760 #mm
T1= 0 #C

#CALCULATIONS
V1= P*V*(273+T1)/((273+T)*760)

#RESULTS
print" volume at STP =",round(V1,1),"litres";

 volume at STP = 20.7 litres


## Example 2.2 , Page no:21¶

In [2]:
import math
from __future__ import division

#initialisation of variables
N= 6*10**23 #molcules
R= 0.0821 #lit atm mole^-1
V= 20 #lit
P= 730 #mm of Hg
T= -20 #C

#CALCULATIONS
M= N*P*V/(760*R*(273+T))

#RESULTS
print"Molecules =",'%.2E'%M," molecules";

Molecules = 5.55E+23  molecules


## Example 2.3 , Page no:21¶

In [3]:
import math
from __future__ import division

#initialisation of variables
P= 100 #cm
m= 2*10**20 #molecules
N= 6*10**23
R= 0.0821 #lit atm mole^-1
T= 27 #C

#CALCULATIONS
V= m*R*(T+273)*760*100/(N*P)

#RESULTS
print"Volume =",round(V,2),"cm^3";

Volume = 6.24 cm^3


## Example 2.4 , Page no:21¶

In [4]:
import math
from __future__ import division

#initialisation of variables
P= 752 #mm
V= 0.2 #lit
T= 21 #C
R= 0.0821 #lit atm mole^-1
m= 0.980 #gms

#CALCULATIONS
M= m*R*(T+273)*760/(V*P)

#RESULTS
print"molecular weight of chloroform =",round(M,1),"gmsper mole";

molecular weight of chloroform = 119.5 gmsper mole


## Example 2.5 , Page no:23¶

In [5]:
import math
from __future__ import division

#initialisation of variables
R= 8.31*10**7 #ergs mole^-1
T= 27 #C
M= 28 #gram per mole

#CALCULATIONS
c= math.sqrt(3*R*(273+T)/M)

#RESULTS
print"root-mean-square velocity =",'%.2E'%c,"cm per sec";

root-mean-square velocity = 5.17E+04 cm per sec


## Example 2.6 , Page no:24¶

In [6]:
import math
from __future__ import division

#initialisation of variables
P= 23.8 #mm
V= 0.5 #lit
R= 0.0821 #lit atm mole^-1
T= 25 #C

#CALCULATIONS
P1= 760-P
n= P1*V/(760*R*(273+T))
V1= V*1000*P1*273/(760*(T+273))

#RESULTS
print"Volume of oxygen =",round(V1),"ml";

Volume of oxygen = 444.0 ml


## Example 2.7 , Page no:27¶

In [7]:
import math
from __future__ import division

#initialisation of variables
t= 20 #min
t1= 19.4 #min
M= 32 #gms

#CALCULATIONS
x= M*t1**2/t**2

#RESULTS
print"molecular weight of ethane =",round(x,1),"gms";

molecular weight of ethane = 30.1 gms


## Example 2.8 , Page no:28¶

In [8]:
import math
from __future__ import division

#initialisation of variables
R= 8.31*10**7 #ergs mole^-1
T= 27 #C
M= 28 #gram per mole

#CALCULATIONS
c= math.sqrt(3*R*(273+T)/M)

#RESULTS
print"root-mean-square velocity =",'%.2E'%c,"cm per sec";

root-mean-square velocity = 5.17E+04 cm per sec


## Example 2.9 , Page no:28¶

In [9]:
import math
from __future__ import division

#initialisation of variables
V= 5.16*10**14 #cm per sec
M2= 28 #gms
M1= 2.02 #gms

#CALCULATIONS
c1= V*math.sqrt(M2/M1)

#RESULTS
print"Velocity of hydrogen molecule =",'%.2E'%c1,"cm per sec";

Velocity of hydrogen molecule = 1.92E+15 cm per sec


## Example 2.10 , Page no:30¶

In [10]:
import math
from __future__ import division

#initialisation of variables
V= 0.5 #lit
T= 50 #C
n= 1 #mole
R= 0.0821 #lit atm mole^-1
a= 4.28*10**-2 #litres mole^-1
b= 3.6 #arm mole^-2 lit^2

#CALCULATIONS
P= n*R*(273+T)/V
P1= (n*R*(T+273)/(V-n*a))-(b/V**2)

#RESULTS
print"Pressure =",round(P),"atm";
print"Pressure using vanderwals equation=",round(P1,1),"atm";

Pressure = 53.0 atm
Pressure using vanderwals equation= 43.6 atm