Originally Posted by **werehk** For a graph with pV against p, it should be a straight horizontal line. However, regarding the slope, slope equals=V = 0 , isn't that ridiculous? |

The slope of a horizontal line is 0. You are saying that the slope should equal V which is 0, or is this a typo?

The relationship expressed by a p vs. V plot can, in general, be complicated. For an ideal gas we easily have that the pressure is inversely proportional to the volume, so the graph is a curve. However for different physical systems we can typically arrange the system to have a variety of different behaviors, on of which is that the pressure is independent of the volume, ie. the slope of the p vs. V graph is 0.

-Dan