Your lungs hold 4.2 L of air at a temperature of $27 ^ { \circ } \mathrm { C }$ and a pressure of 101.3 kPa. How many moles of air do your lungs hold? $( R = 8.31 \mathrm {~J} / \mathrm { mol } \cdot \mathrm { K } )$
A) 0.17 moles
B) 0.15 moles
C) 0.19 moles
D) 0.21 moles
E) 0.23 moles

Question

Your lungs hold  4.2 L of air at a temperature of $27 ^ { \circ } \mathrm { C }$ and a pressure of  101.3 kPa. How many moles of air do your lungs hold? $( R = 8.31 \mathrm {~J} / \mathrm { mol } \cdot \mathrm { K } )$
A)  0.17  moles
B)  0.15  moles
C)  0.19  moles
D)  0.21 moles
E)  0.23  moles

Quizplus · Accepted Answer

Using the ideal gas law $ PV = nRT $, convert temperature to Kelvin (300 K) and solve for n: $ n = \frac{PV}{RT} = \frac{(101.3 \times 10^3 \, \text{Pa})(4.2 \times 10^{-3} \, \text{m}^3)}{8.31 \, \text{J/mol K} \times 300 \, \text{K}} \approx 0.17 \, \text{moles} $.

Your Lungs Hold 4 27∘C27 ^ { \circ } \mathrm { C }27∘C

Your Lungs Hold 4 $27 ^ { \circ } \mathrm { C }$