Van der waal equation

[meteorstar]

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Can someone explain to me in Van der waal equation: (P + n^2a/v^2)(v - nb) = nRT, why does largest a = lowest pressure and largest b = largest v.

Thank you in advance

 

[CrazyChemist]

Can someone explain to me in Van der waal equation: (P + n^2a/v^2)(v - nb) = nRT, why does largest a = lowest pressure and largest b = largest v.

Thank you in advance

You need to re-arrange the equation. At least that's how I would do it!

(P + n^2a/v^2)(v - nb) = nRT
P = [nRT/(v - nb)] -(n^2a/v^2)
For a: P ~ -n^2a, as a increases -n^2a becomes more negative and pressure decreases

(P + n^2a/v^2)(v - nb) = nRT
(P + n^2a/v^2) = nRT/(v - nb)
(v - nb)(P + n^2a/v^2) = nRT
(v - nb) = nRT/[(P + n^2a/v^2)]
v = nRT/[(P + n^2a/v^2)] + nb

For b: v ~ nb, as b increases, nb increases and volume becomes larger