# A child's lungs can hold 2.20 L. How many grams of air do her lungs hold at a pressure of 102 kPa and a body temperature of 37°C?

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Use a molar mass of 29 g for air, which is about 20% #O# (32 g/mol) and 80% #N_2# (28 g/mol).

Use a molar mass of 29 g for air, which is about 20%

##### 1 Answer

#### Explanation:

The ideal gas equation gives us:

Rearranging:

Converting

Since we are told that 1 mole weighs 29g then the mass of air is given by:

Sub note:

The Ideal Gas Equation applies to a closed system and the lungs are not a closed system. Lets assume that at 2.20 L the child hold its breath (though not for too long).