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For a gas obeying the van der Waals equation, the critical compressibility factor () is given by:
A real gas behaves most ideally at:
Low pressure and high temperature, minimizing intermolecular forces and molecular volume.
High pressure and low temperature, maximizing intermolecular forces.
High pressure and high temperature, where kinetic energy dominates.
Low pressure and low temperature, where both intermolecular forces and volume are negligible.
For a van der Waals gas with and , the Boyle temperature () is:
1218 K
1000 K
2436 K
609 K
The compressibility factor (Z) for a gas at its critical point (, ) is:
Always equal to 1
Greater than 1
Less than 1, typically around 0.3
Zero
Which of the following is NOT a correct relationship between critical constants (, , ) and van der Waals constants (, ) for a real gas?
Tc = 8a/27Rb
Pc = a/27b^2
Vc = 3b
b = Vc
The critical temperature of a gas is the temperature:
At which it solidifies under high pressure.
Below which it can be liquefied by applying sufficient pressure.
Above which it cannot be liquefied, regardless of the pressure applied.
At which its vapor pressure equals atmospheric pressure.
The critical density of a substance is related to its van der Waals constants ( and ) by:
\frac{1}{3b}
\frac{b}{3a}
\frac{a}{3b}
\frac{3a}{b}
At the critical point of a substance, the distinction between the liquid and gaseous phases:
Disappears.
Becomes more pronounced.
Reverses.
Depends on the pressure.
Which of the following is NOT a critical constant?
Triple Point Temperature
Critical Temperature
Critical Pressure
Critical Volume
The critical pressure is the pressure required to liquefy a gas:
At its critical temperature.
At its boiling point.
At 0Β°C.
At its freezing point.
