Ideal Gas Plot (density/pressure vs pressure)

• atomos

  8 May 12, 10:47

  Just need a quick confirmation regarding ideal gas plots.

  pV = nRT.

  For a vertical axis to be density(rho) /pressure,

  I arrived at rho/p= M/RT

  So at constant temperature, plotting rho/p vs p would give us a flat line?

  Wondering if I've overlooked anything.

• UltimaOnline

  8 May 12, 11:17

  Originally posted by atomos:

  Just need a quick confirmation regarding ideal gas plots.

  pV = nRT.

  For a vertical axis to be density(rho) /pressure,

  I arrived at rho/p= M/RT

  So at constant temperature, plotting rho/p vs p would give us a flat line?

  Wondering if I've overlooked anything.

  
  Density = mass / volume

  Since for a constant n, mass is also constant, hence regard density as constant/V

  Accordingly, density / pressure = constant/(PV)

  Since pressure and volume have an inversely proportional relationship (ie. when you increase pressure volume decreases; when you increase volume pressure decreases), hence PV = constant.

  So if y-axis is density/pressure = constant/(constant) and x-axis is P, hence a straight horizontal line is obtained.

   

• atomos

  8 May 12, 11:35

  Thanks!

  I was originally looking from the angle that 

  rho/pressure = M/RT.

  and M/RT is constant at constant temperature.

  Therefore rho/pressure= constant. (flat horizontal line).

  But your approach also makes sense.