STATES OF MATTER (GASES) JEE

If Z is the compressibility factor, van der Waals’ equation at low pressure can be written as :

• Z=1-Pb/RT

• Z=1+Pb/RT

• Z = 1+RT/Pb

• Z = 1-a/V_mRT

Which intermolecular force is most responsible in allowing xenon gas to liquefy?

• Instantaneous dipole induced dipole

• Ion dipole

• Ionic

• Dipole-dipole

The temperature at which oxygen molecules have the same root mean square

speed as helium atoms have at 300 K is :

(Atomic masses : He = 4 u, O = 16 u)

• 1200 K

• 600 K

• 300 K

• 2400 K

The compressibility factor for a real gas at high pressure is :

• 1-Pb/RT

• 1+ RT/Pb

• 1

• 1+Pb/RT

The relationship among most probable velocity, average velocity and root mean

Square velocity is respectively :

• √2 : √(8/π) : √3

• √2 :√3 : √(8/π )

• √3 : √(8/π) : √2

• √(8/π) : √3 : √2

Value of gas constant R is

• 0.082 L atm

• 0.987 cal mol^-1 K^-1

• 8.3 J mol^-1 K^-1

• 83 erg mol^-1K^-1

By how many folds the temperature of a gas would increase when the root mean

Square velocity of the gas molecules in a container of fixed volume is increased from 5×10⁴ cm/s to 10×10⁴ cm/s?

• four

• three

• two

• six

Kinetic theory of gases proves

• Only boyle’s law

• Only Charle’s law

• Only Avogadro’s law

• all of these

Which one of the following is the wrong assumption of kinetic theory of gases?

• All the molecules move in a straight line between collision and with the same velocity.

• Molecules are separated by great distances compared to their sizes.

• Pressure is the result of elastic collision of molecules with the container’s wall.

• Momentum and energy always remain conserved.

‘a’ and ‘b’ are Vander Waal’s constants for gases. Chlorine is more easily liquified than ethane because:

• a for Cl₂ < a for C₂H₆ but b for Cl₂ > b for C₂H₆

• a for Cl₂ > a for C₂H₆ but b for Cl₂ < b for C₂H₆

• a and b for Cl₂ > a and b for C₂H₆

• a and b for Cl₂ < a and b for C₂H₆