Explain how the gas laws apply to the act of breathing. describe the changes that occur in each step of the process in terms of the pressure, volume, temperature, and moles of gas present for each step, identify which variables are constant, and which are changing name the gas law or gas laws that apply to the process create and solve a sample calculation using realistic values of pressure, temperature, amount of gas, and volume. !

When you in inhale, you move your diaphragm down increasing the volume of the cavity in your ribs (its called pleural cavity). This lowers the pressure inside your lungs. When the pressure in your lungs is less than the atmospheric pressure, air draws inwards. Ideal gas law: PV=nRT -> assume nRT are constant for our purposes. then we allow one system to be equal to the same system at different conditions, thus: P1V1=P2V2 (Boyles Law) assume P1=1 atm and V1=1 L (keeping the numbers simple to avoid confusion). when the V is increased (for example say doubled) V2=2 L, then: (1 atm)*(1 L)=P2*(2 L) -> P2=0.5 atm The pressure was decreased. Apply the same logic for exhalation.