The van der Waals equation is an equation of state for a fluid composed of particles that have a non-zero volume and a pairwise attractive inter-particle force (such as the van der Waals force.) It was derived by Johannes Diderik van der Waals in 1873, who received the Nobel prize in 1910 for "his work on the equation of state for gases and liquids". The equation is based on a modification of the ideal gas law and approximates the behavior of real fluids, taking into account the nonzero size of molecules and the attraction between them. Van der Waals law wiki article

Solve for	Equations
P
T
n
V

Pressure (P)		atmosphere (standard) atmosphere (technical) bar barye (cgs unit) centimetre of mercury centimetre of water (4 C) foot of mercury (conventional) foot of water (39.2 F) inch of mercury (conventional) inch of water (39.2 F) kilogram-force per square millimetre kip per square inch micron (micrometre) of mercury millimetre of mercury millimetre of water (3.98 C) pascal (SI unit) pieze (mts unit) pound per square foot pound per square inch poundal per square foot short ton per square foot torr
Temperature (T)		degree Celsius degree Delisle degree Fahrenheit degree Newton degree Rankine degree Reaumur degree Romer degree Kelvin (SI unit)
Volume (V)		acre-foot acre-inch barrel (Imperial) barrel (petroleum) barrel (U.S. dry) barrel (U.S. fluid) board-foot bucket (Imperial) bushel (Imperial) bushel (U.S. dry heaped) bushel (U.S. dry level) butt, pipe coomb cord (firewood) cord-foot cubic fathom cubic foot cubic inch cubic metre (SI unit) cubic mile cubic yard cup (breakfast) cup (Canadian) cup (metric) cup (U.S. customary) cup (U.S. food nutrition labeling) dash (Imperial) dash (U.S.) dessertspoon (Imperial) drop (Imperial) drop (Imperial) (alt) drop (medical) drop (metric) drop (U.S.) drop (U.S.) (alt) fifth firkin fluid drachm (Imperial) fluid dram (U.S.); U.S. fluidram fluid scruple (Imperial) gallon (beer) gallon (Imperial) gallon (U.S. dry) gallon (U.S. fluid; Wine) gill (Imperial); Noggin gill (U.S.) hogshead (Imperial) hogshead (U.S.) jigger (bartending) kilderkin lambda last litre load minim (Imperial) minim (U.S.) ounce (fluid Imperial) ounce (fluid U.S. customary) ounce (fluid U.S. food nutrition labeling) peck (Imperial) peck (U.S. dry) perch pinch (Imperial) pinch (U.S.) pint (Imperial) pint (U.S. dry) pint (U.S. fluid) pony pottle; quartern quart (Imperial) quart (U.S. dry) quart (U.S. fluid) quarter; pail register ton sack (Imperial); bag sack (U.S.) seam shot strike (Imperial) strike (U.S.) tablespoon (Australian metric) tablespoon (Canadian) tablespoon (Imperial) tablespoon (metric) tablespoon (U.S. customary) tablespoon (U.S. food nutrition labeling) teaspoon (Canadian) teaspoon (Imperial) teaspoon (metric) teaspoon (U.S. customary) teaspoon (U.S. food nutrition labeling) timber foot ton (displacement) ton (freight) ton (water) tun wey (U.S.)
Gas constant (R)	(std) 8.3144621 8.3144621	J/(mol*K)
Number of moles (n)
Parameters (gas)	CustomAcetic acidAcetic anhydrideAcetoneAcetonitrileAcetyleneAmmoniaAirArgonBenzeneBromobenzeneButaneCarbon dioxideCarbon disulfideCarbon monoxideCarbon tetrachlorideChlorineChlorobenzeneChloroethaneChloromethaneCyanogenCyclohexaneDiethyl etherDiethyl sulfideDimethyl etherDimethyl sulfideEthaneEthanethiolEthanolEthyl acetateEthylamineFluorobenzeneFluoromethaneFreonGermanium tetrachlorideHeliumHexaneHydrogenHydrogen bromideHydrogen chlorideHydrogen selenideHydrogen sulfideIodobenzeneKryptonMercuryMethaneMethanolNeonNitric oxideNitrogenNitrogen dioxideNitrous oxideOxygenPentanePhosphinePropaneSilaneSilicon tetrafluorideSulfur dioxideTin tetrachlorideTolueneWaterXenon
Measure of the attraction between the particles (a)		J*m3/mol2
Volume excluded by a mole of particles (b)		m3/mol