Student Question

# The world record for a human holding his or her breath is 11 minutes, but most people can only hold it for a few minutes. If a woman holds her breath at the maximum lung capacity (4.2 L), calculate the final pressure in her lungs if her body temperature is 37.0ºC,  the ambient air temperature in the room is 20.0ºC and the pressure is 1.08 atm.

It sounds like you need to find out how the pressure of the air trapped in the woman's lungs will be affected by the temperature change as the air warms. It appears that you are to assume that the air will reach her body temperature of 37ºC during the time that she holds her breath.

Since there is a fixed number of moles of gas at constant volume, the pressure will vary directly with the Kelvin temperature. We can use the gas law equation that relates pressure and temperature:

`P_1/T_1 = P_2/T_2`

Here's the information you're given:

P1 = 1.08 atm

T1 = (20ºC + 273) = 293 Kelvins

T2 = (37ºC + 273) = 310 Kelvins

Rearrange the equation to isolate P2:

`P_2 = [(P_1)(T_2)]/(T_1)`

P2 = (1.08 atm)(310 K)/(293 K) = 1.14 atm