Johannes Diederik Van Der Waals was born november 23, 1837, in Leiden, Netherlands, and died march 9, 1923 in Amsterdam.
After elementary education, and studying at Leydon university in his spare time during 1862-65, he became a teacher, soon after he obtained a teaching cirtificate in maths and phsysics. He earned his doctorate after the publication "on the contineuity of the liquid and gasious states".
Van Der Vaals knew that the perfect gas law was not true to actual states of molecules in the gas phase so started working on his own equation of state. In 1981 he published what is now known as the perfect gas law, or Van Der Vaals equation. For his work on the kinetic theory of gases he won a nobel prize. Later he was appointed professer of physics at the university of Amsterdam.
In 1873 Van Der Waals got noticed on account of his extention
of the ideal gas law,
pV=nRT
He aknowleged that this gas law made two major assumptions, firstly that molecules have no volume, and second, that there are no attractive forces between molecules. Van Der Waals equation was deriver from the aknowledgment that both these two assumptions are wrong.
In 1881 he introduced new factors into the ideal gas law, thus
making the real gas law, otherwise known as the Van Der Waals equation,
(p + an2/V2)(V - nb) = nRT
| Compound | a (L2 - atm/mol2) | b(L/mol) |
| He | 0.0341 | 0.0237 |
| Ne | 0.211 | 0.0171 |
| Ar | 1.34 | 0.0322 |
| H2 | 0.244 | 0.0266 |
| N2 | 1.39 | 0.0391 |
| O2 | 1.36 | 0.0318 |
| Cl2 | 6.49 | 0.0562 |
| H |
5.46 | 0.0305 |
| CH4 | 2.25 | 0.0428 |
| CO2 | 3.59 | 0.0427 |
| CCl4 | 20.40 | 0.1383 |
"a" is reflective of the amount of intermoleculer forces between the molecules. The more intermlecular forces the higher the value.
In the equation you will notice that "a" is added in the equation. This is because the measured pressure is in fact smaller than the actual pressure.
"b" is a value which is dependent upon the size of the molecules withhin the container. Its quite simple really, the larger the molecule, the larger the value
In the equation "b" is subtracted from the measured value, V, to give an actual value taking into account the molecules within the container.
Van Der Waals work on the ideal gas equation lead him to recieve the Nobel prize in physics in 1910
Due to his work he had the honour of having