The Ideal Gas Law: Mastery Test

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

Constants:
[tex]\[ R = 8.314 \frac{L \cdot kPa}{mol \cdot K} \][/tex]

Question:
A pressure cooker contains 5.68 liters of air at a temperature of 394 K. If the absolute pressure of the air in the pressure cooker is 202.65 kPa, how many moles of air are in the cooker?

Answer:
The cooker contains \_\_\_\_ moles of air.



Answer :

To solve for the number of moles of air in the pressure cooker, we will use the Ideal Gas Law, which is given by the 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.

Given the following values:
- Pressure [tex]\(P = 2024 \, \text{kPa}\)[/tex],
- Volume [tex]\(V = 5.68 \, \text{liters}\)[/tex],
- Temperature [tex]\(T = 394 \, \text{K}\)[/tex],
- Ideal Gas Constant [tex]\(R = 8.314 \, \frac{\text{L} \cdot \text{kPa}}{\text{mol} \cdot \text{K}}\)[/tex],

we need to solve for the number of moles, [tex]\( n \)[/tex].

1. Rearrange the Ideal Gas Law to solve for [tex]\( n \)[/tex]:

[tex]\[ n = \frac{PV}{RT} \][/tex]

2. Substitute the given values into the equation:

[tex]\[ n = \frac{(2024 \, \text{kPa}) \cdot (5.68 \, \text{liters})}{(8.314 \, \frac{\text{L} \cdot \text{kPa}}{\text{mol} \cdot \text{K}}) \cdot (394 \, \text{K})} \][/tex]

3. Simplify the expression by performing the multiplication and division:

[tex]\[ n = \frac{2024 \times 5.68}{8.314 \times 394} \][/tex]

4. The exact calculation leads to:

[tex]\[ n \approx 3.5095594367765703 \, \text{moles} \][/tex]

Thus, the number of moles of air in the pressure cooker is approximately [tex]\(3.51 \, \text{moles}\)[/tex] when rounded to two decimal places.