Boyle's law of the gas, and "k" is a constant. The equation states that the product of pressure and volume is a constant for a given mass of confined gas and this holds as long as the temperature is constant. For comparing the same substance under two different sets of conditions, the law can be usefully expressed as The equation shows that, as volume increases, the pressure of the gas decreases in proportion. Similarly, as volume decreases, the pressure of the gas increases. The law was named after chemist and physicist Robert Boyle, who published the original law in 1662. This relationship
Standard cubic foot of the label "standard", there is a variety of definitions, mainly depending on the type of gas. Since, for a given volume, the quantity is proportional to the pressure and (absolute) temperature, each definition fixes base values for pressure and temperature. The ideal gas law allows then to compute the quantity per unit of volume for actual pressures and temperatures. Since natural gas is an imprecise mix of various molecular species, chiefly methane but with varying proportions of other gases, a standard cubic foot of natural gas does not represent a precise unit of mass, but only a molecular quantity,