(a)
Interpretation:
The value of the compressibility factor for an ideal gas is to be stated.
Concept introduction:
The
Answer to Problem 1.36E
The ideal gas equation is
Explanation of Solution
In many circumstances such as at low temperature and high pressures the gases deviate from the ideal gas equation.
The equation (1) can be written for non-ideality with correction as,
Where,
P = Pressure
Z = Compressibility factor
R = Universal gas constant
T = Temperature
Therefore, the compressibility factor can be written as,
This is simplest form of equation of state of real gas. The key factor of equation (3) is that the compressibility factor, Z, is not a constant. Basically, the value of ‘Z’ varies from one gas to another gas as well as varies with the pressure and temperature of the gas under consideration. Thus, it should be evaluated experimentally. The plot of ‘Z’ versus pressure at constant temperature of plot of ‘Z’ versus pressure at varying temperatures gives the readily obtaining interpolated values of ‘Z’ between the experimentally determined values.
The compressibility factor ‘Z’ can be expressed in another form as,
The factors affecting the compressibility values are;
1. When the gas pressure approaches 0, the value of Z tends toward 1. In this case all gases show ideal behavior.
2. When the gas pressure is at intermediate level, the value of Z is less than 1. In this case actual volumes to be less than the ideal values due to intermolecular forces of attraction.
3. When the gas pressure is high, the value of Z is greater than 1 and tends toward infinity. In this case the actual volumes to be greater than the ideal values due to intermolecular repulsive forces.
Thus, the value of the compressibility factor for an ideal gas is stated.
(b)
Interpretation:
‘The value varies with
Concept introduction:
The ideal
Answer to Problem 1.36E
Since, the compressibility factor Z is having the variables p, V, and T, its value will certainly vary with the terms of p, V, and T. Generally, the farther the value of Z is from ‘one’ the gas behaves less ideally.
Explanation of Solution
In many circumstances such as at low temperature and high pressures the gases deviate from the ideal gas equation
The equation (1) can be written for non-ideality with correction as,
Where,
P = Pressure
Z = Compressibility factor
R = Universal gas constant
T = Temperature
Therefore, the compressibility factor can be written as,
This is simplest form of equation of state of real gas. The key factor of equation (3) is that the compressibility factor, Z, is not a constant. Basically, the value of ‘Z’ varies from one gas to another gas as well as varies with the pressure and temperature of the gas under consideration. Thus, it should be evaluated experimentally. The plot of ‘Z’ versus pressure at constant temperature of plot of ‘Z’ versus pressure at varying temperatures gives the readily obtaining interpolated values of ‘Z’ between the experimentally determined values.
The compressibility factor ‘Z’ can be expressed in another form as,
The factors affecting the compressibility values are;
1. When the gas pressure approaches 0, the value of Z tends toward 1. In this case all gases show ideal behavior.
2. When the gas pressure is at intermediate level, the value of Z is less than 1. In this case actual volumes to be less than the ideal values due to intermolecular forces of attraction.
3. When the gas pressure is high, the value of Z is greater than 1 and tends toward infinity. In this case the actual volumes to be greater than the ideal values due to intermolecular repulsive forces.
Thus, ‘The value varies with
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Chapter 1 Solutions
Physical Chemistry
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