Question

Whitney's tidal volume, which is the volume of air that she inhales and exhales, was 0.56 L . Her tidal volume was measured at a body temperature of 37 ∘C and a pressure of 744 mmHg . How many moles of nitrogen does she inhale in one breath if air contains 78% nitrogen?

Answer 1

Given:

Volume of air inhaled V = 0.56 L

Temperature T = 37 C = 37 +273 = 310 K

Pressure P = 744 mmHg = 744/760 = 0.979 atm

% N2 in air = 78%

To determine:

The moles of N2 inhaled in one breath

Explanation:

Step 1: Calculate the moles of air inhales

Based on the ideal gas law:

PV = nRT

where P = pressure, T = temperature, V = volume, n = # moles

R = gas constant = 0.0821 L atm/mol-K

n = PV/RT = 0.979 * 0.56/0.0821*310 = 0.0215 moles of air

Step 2: Calculate the moles of N2

It is given that air contains 78% N2

Therefore:

moles of N2 = 0.0215 * 78/100 = 0.0168 moles

Ans: moles of N2 = 0.0168