Question

A boy with pneumonia has lungs with a volume of 1.9 L that fill with 0.080 mol of air when he inhales. When he exhales, his lung volume decreases to 1.5 L. Enter the number of moles of gas that remain in his lungs after he exhales. Assume constant temperature and pressure. g

Answer 1

Answer: The number of moles of gas remaining in the lungs is 0.063 moles

Explanation:

The relationship of number of moles and volume at constant temperature and pressure was given by Avogadro's law. This law states that volume is directly proportional to number of moles at constant temperature and pressure.

The equation used to calculate number of moles is given by:

$\frac{V_1}{n_1}=\frac{V_2}{n_2}$

where,

$V_1\text{ and }n_1$ are the initial volume and number of moles

$V_2\text{ and }n_2$ are the final volume and number of moles

We are given:

$V-1=1.9L\\n_1=0.080mol\\V_2=1.5L\\n_2=?$

Putting values in above equation, we get:

$\frac{1.9}{0.080}=\frac{1.5}{n_2}\\\\n_2=\frac{1.5\times 0.080}{1.9}=0.063$

Hence, the number of moles of gas remaining in the lungs is 0.063 moles