Gas Pressure

2.3  Gas Pressure

Explaining pressure using the kinetic theory of gases.

  • Gas molecules move freely and randomly
  • Gas molecules hit wall of container and change direction (elastic collision) resulting in a change in momentum
  • Change of momentum per time produce force
  • Force per unit area produce pressure

Factors incluencing the gas pressure

  1.  Gas density
    • \(\rho\;\uparrow\;P\uparrow\\ \rho\;\downarrow\;P\downarrow\)

  2. Temperature
    • \(T\;\uparrow\;P\uparrow\\ T\;\downarrow\;P\downarrow\)

Instruments to measure gas pressure

  • Bourdon gauge
  • Manometer
  Another formula for pressure  
  •  \(P=\dfrac{F}{A}\), where P = pressure, F = force , A = area.
  • \(P\propto\dfrac{1}{A}\rightarrow P\text{ is inversely proportional to }A\)
  • \(A\uparrow\;\;P\downarrow\)