14.1. The Ideal Gas Law http://www.ck12.org
Guy-Lussac’s Law
Joseph Louis Gay-Lussac (1778-1850),Figure14.8, is also credited with stating that when the volume of a gas is
held constant, the pressurePis directly related to the temperatureT(Kelvin),P∝TFigure14.9. This graph is also
extrapolated for temperatures close to absolute zero.
FIGURE 14.8
Guy-LussacFIGURE 14.9
The Mass of a Gas
For the three laws above, we assumed that the mass of the gas was constant. But the mass of a gas can increase
or decrease. Fill a tire with air (a gas) and there is an increase in mass. If the air flows out of the tire, the mass
decreases. In both cases, the volume of the tire will change. Once a tire is close to its rated pressure, however, filling
it with more air will hardly increase the volume. But the pressure can still increase a good deal. The increase in
pressure is due to the increase in mass of the gas because there are more molecules hitting the inside of the tire. Both
volumeVand pressureP, therefore, increase with mass in direct proportionm→P∝mandV∝m.