Perhaps you meant chemistry, where V refers to volume.
Ideal Gas Law
"The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations.
For the most part gases all follow the equation PV = nRT where P is pressure (in atmospheres), V is volume (in liters), n is number of moles, and T is temperature (in degrees Kelvin). R is a constant, equal to 0.08206 L atm/moleK."
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