Consider the van der Waals constants, a and b, for the following gases.
Gas: Ar, Ne, Kr, Xe
a/(atm dm⁶ mol⁻²): 1.3, 0.2, 5.1, 4.1
b/(10⁻² dm³ mol⁻¹): 3.2, 1.7, 1.5, 0.9
Which gas is expected to have the highest critical temperature?

Question

Consider the van der Waals constants, a and b, for the following gases.
Gas: Ar, Ne, Kr, Xe
 a/(atm dm⁶ mol⁻²): 1.3, 0.2, 5.1, 4.1
 b/(10⁻² dm³ mol⁻¹): 3.2, 1.7, 1.5, 0.9
Which gas is expected to have the highest critical temperature?

Accepted Answer

Xe. Critical temperature Tc = 8a/(27Rb), so it scales with a/b. Computing a/b: Ar=0.41, Ne=0.12, Kr=3.4, Xe=4.56. Xe has the largest a/b and thus the highest critical temperature.

Consider the van der Waals constants, a and b, for the following gases. Gas: Ar, Ne, Kr, Xe a/(atm dm⁶ mol⁻²): 1.3, 0.2, 5.1, 4.1 b/(10⁻² dm³ mol⁻¹): 3.2, 1.7, 1.5, 0.9 Which gas is expected to have the highest critical temperature?

Solution

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