Gas Laws Fact Sheet

\begin{tabular}{|l|l|}
\hline Ideal gas law & [tex]$PV = nRT$[/tex] \\
\hline Ideal gas constant & [tex]$R = 8.314 \frac{L \cdot kPa}{mol \cdot K}$[/tex] \\
& or \\
& [tex]$R = 0.0821 \frac{L \cdot atm}{mol \cdot K}$[/tex] \\
\hline Standard atmospheric pressure & [tex]$1 atm = 101.3 kPa$[/tex] \\
\hline Celsius to Kelvin conversion & [tex]$K = ^{\circ}C + 273.15$[/tex] \\
\hline
\end{tabular}

A human lung at maximum capacity has a volume of 3.0 liters. If the partial pressure of oxygen in the air is 21.1 kilopascals and the air temperature is 295 K, how many moles of oxygen are in the lung?

A. [tex]$\quad 0.026 \, mol$[/tex]
B. [tex]$\quad 0.12 \, mol$[/tex]
C. [tex]$\quad 2.6 \, mol$[/tex]
D. [tex]$\quad 13 \, mol$[/tex]



Answer :

To determine the number of moles of oxygen in the lung at maximum capacity, we can use the Ideal Gas Law equation:

[tex]\[ PV = nRT \][/tex]

where:
- [tex]\( P \)[/tex] is the pressure,
- [tex]\( V \)[/tex] is the volume,
- [tex]\( n \)[/tex] is the number of moles,
- [tex]\( R \)[/tex] is the ideal gas constant,
- [tex]\( T \)[/tex] is the temperature in Kelvin.

Here's how we can find the number of moles step-by-step:

1. Identify the given values:
- Volume ([tex]\( V \)[/tex]) = 3.0 liters
- Pressure ([tex]\( P \)[/tex]) = 21.1 kilopascals
- Temperature ([tex]\( T \)[/tex]) = 295 Kelvin
- Ideal gas constant ([tex]\( R \)[/tex]) = 8.314 L·kPa/(mol·K)

2. Rearrange the Ideal Gas Law to solve for [tex]\( n \)[/tex] (the number of moles):
[tex]\[ n = \frac{PV}{RT} \][/tex]

3. Substitute the given values into the equation:
[tex]\[ n = \frac{(21.1 \text{ kPa}) \times (3.0 \text{ L})}{(8.314 \text{ L·kPa/(mol·K)}) \times (295 \text{ K})} \][/tex]

4. Perform the calculation:
[tex]\[ n = \frac{63.3 \text{ kPa·L}}{2459.13 \text{ L·kPa/(mol·K)}} \][/tex]

5. Simplify the fraction to find the number of moles [tex]\( n \)[/tex]:
[tex]\[ n = 0.02580902949079152 \text{ mol} \][/tex]

6. Rounding the answer to an appropriate number of significant figures:
Given that the initial values (3.0, 21.1, and 295) have three significant figures, the result should be rounded to three significant figures as well:

[tex]\[ n \approx 0.026 \text{ mol} \][/tex]

So, the number of moles of oxygen in the lung at maximum capacity is closest to option A.

Final Answer:
A. [tex]\(\quad 0.026 \text{ mol} \)[/tex]