Know the Gas Laws

The symbols that will be used in the mathematical expression of the various gas laws are:

V ₁ = Volume of the gas in cubic ft with original conditions

V ₂ = Volume of gas in cubic ft under the second set of conditions

T ₁ = Initial temperature of the gas in R( F + 460)

T ₂ = Temperature of gas under second conditions R

P ₁ = Pressure of gas in psia under original conditions

P ₂ = Pressure of gas in psia under second conditions

Any other symbols used in mathematically expressing the gas laws will be explained at the time of their introduction.

Boyle's law. If the temperature remains the same, the volume of a given quantity of gas will vary inversely as the absolute pressure. This may be expressed mathematically as:

Inasmuch as in the application of Boyle's Law we are generally interested in the volume at a second set of pressure conditions, a rearrangement of the formula more readily used is:

Example. A quantity of gas at a pressure of 42 psig has a volume of 1,000 cubic ft. If the gas is compressed to 100 psig, what volume would it occupy? Assume the barometric pressure to be 14.2 psia and the temperature to remain the same. Substituting in the second arrangement of the formula for Boyle's Law above would give:

Charles' law (sometimes called...