Which of the following variables is NOT included in the ideal gas equation PV = nRT?

• A. Temperature (T)
• B. Pressure (P)
• C. Density (d)
• D. Volume (V)

Answer: (C)

Verified step by step guidance

1. Recall the ideal gas equation: \(PV = nRT\), where \(P\) is pressure, \(V\) is volume, \(n\) is the number of moles, \(R\) is the ideal gas constant, and \(T\) is temperature.
2. Identify each variable in the equation: \(P\) (pressure), \(V\) (volume), \(n\) (amount of gas in moles), and \(T\) (temperature) are all explicitly included.
3. Note that density (\(d\)) is not directly present in the ideal gas equation, although it can be related to the variables through other formulas.
4. Understand that density is defined as mass per unit volume (\(d = \frac{m}{V}\)), and while it can be connected to the ideal gas law by substituting \(n = \frac{m}{M}\) (where \(M\) is molar mass), it is not a variable in the original equation.
5. Therefore, the variable NOT included in the ideal gas equation \(PV = nRT\) is density (\(d\)).