Which statement best describes the gas in a scuba tank according to the ideal gas law?

• A. The gas pressure increases as the volume of the tank decreases, assuming temperature and amount of gas remain constant.
• B. The gas pressure decreases as the amount of gas in the tank increases, assuming volume and temperature remain constant.
• C. The gas pressure is independent of the temperature inside the tank.
• D. The gas pressure remains constant regardless of changes in volume, temperature, or amount of gas.

Answer: (A)

Verified step by step guidance

1. Recall the ideal gas law, which is given by the equation \(P \times V = n \times R \times T\), where \(P\) is pressure, \(V\) is volume, \(n\) is the amount of gas (in moles), \(R\) is the ideal gas constant, and \(T\) is temperature in Kelvin.
2. Understand that in a scuba tank, the volume \(V\) is fixed because the tank is rigid and does not change size, so \(V\) is constant.
3. Recognize that if the temperature \(T\) and the amount of gas \(n\) remain constant, then the pressure \(P\) must also remain constant according to the ideal gas law, since \(P = \frac{nRT}{V}\) and all variables on the right side are constant.
4. Analyze the statements: the pressure cannot increase if volume decreases because volume is fixed; pressure cannot decrease if amount of gas increases because increasing \(n\) increases \(P\); pressure is not independent of temperature because \(P\) depends directly on \(T\); and pressure does not remain constant regardless of changes because it depends on \(n\), \(T\), and \(V\).
5. Conclude that the correct description must reflect the direct relationships in the ideal gas law, particularly that pressure increases if volume decreases (if volume were to change), assuming temperature and amount of gas remain constant.