The relationship between the partial pressure of a gas (P) and the number of moles of that gas (n) is best represented by which of the following graphs?

• A.
• B.
• C.
• D.

Answer: (D)

Verified step by step guidance

1. Recall the ideal gas law equation: \( PV = nRT \), where \( P \) is the pressure, \( V \) is the volume, \( n \) is the number of moles, \( R \) is the ideal gas constant, and \( T \) is the temperature.
2. Rearrange the ideal gas law to express pressure \( P \) in terms of the number of moles \( n \): \( P = \frac{nRT}{V} \).
3. Assume that the volume \( V \) and temperature \( T \) are constant. This implies that \( P \) is directly proportional to \( n \), i.e., \( P \propto n \).
4. A direct proportionality between \( P \) and \( n \) means that as the number of moles \( n \) increases, the pressure \( P \) increases linearly.
5. Identify the graph that represents a linear relationship between \( P \) and \( n \). This graph should be a straight line passing through the origin, indicating that \( P \) increases linearly with \( n \).