On a cold day, a person takes in a breath of 450 mL of air at 86.6 kPa and –10°C. What is the...?

Question

On a cold day, a person takes in a breath of 450 mL of air at 86.6 kPa and –10°C. What is the volume of this air in the lungs at 37°C and 650 mm Hg?

Answer 1

Use combined gas law

P1 V1 / T1 = P2 V2 / T2

But remember to convert the temperature to Kelvin.

Then just plug in the numbers and solve for V2

Answer 2

Charle's Law.
(86.6kPa = 650mmHg, so.. Pressure is constant).

T1 x V2 = T2 x V1
263 K x V2 = 310 x 450
V2 = (310 x 450) ÷ 263
Volume in lungs (V2) = 530mL.

(Alternative route...310/263 = 1.178...1.178 x 450 = 530mL).

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