If Pressure is inversely proportional to volume, theoretically, how does a tire burst if you pump too much air in it? If the volume inside the tire is increasing shouldn’t the pressure decrease?

Question

If Pressure is inversely proportional to volume, theoretically, how does a tire burst if you pump too much air in it? If the volume inside the tire is increasing shouldn’t the pressure decrease?

In: 0

Answer 1

The equation for an ideal gas is:

𝑃𝑉=𝑛𝑅𝑇

P = pressure.
V = volume.
*n* = amount of substance.
R = ideal gas constant.
T = temperature.

Rearranging this gives:

𝑃=𝑛𝑅𝑇(1/𝑉)

So 𝑃 is only inversely proportional to 𝑉 if the constant of proportionality, 𝑛𝑅𝑇, is a constant. And that is a constant only if n (the amount of stuff) is constant. If the amount of stuff changes (ie. you’re pumping it with air) then pressure is not inversely proportional to volume.