In the equation for the Ideal Gas Law, PV = nRT, which of the following variables could be considered unknowns to solve for if the other variables are known?

• A. Only pressure and volume
• B. Only temperature and moles
• C. Pressure, volume, temperature, and moles
• D. Only pressure, volume, and temperature

Answer: (C)

Verified step by step guidance

1. Recall the Ideal Gas Law equation: \(P V = n R T\), where \(P\) is pressure, \(V\) is volume, \(n\) is the number of moles, \(R\) is the ideal gas constant, and \(T\) is temperature.
2. Understand that in this equation, \(R\) is a constant and its value does not change, so it is never an unknown variable to solve for.
3. Recognize that the equation relates four variables: pressure (\(P\)), volume (\(V\)), number of moles (\(n\)), and temperature (\(T\)). If any one of these four variables is unknown, it can be solved for algebraically using the other three known values.
4. For example, if \(P\), \(V\), and \(T\) are known, you can solve for \(n\) by rearranging the equation to \(n = \frac{P V}{R T}\). Similarly, if \(n\), \(V\), and \(T\) are known, you can solve for \(P\) by \(P = \frac{n R T}{V}\), and so on for the other variables.
5. Therefore, any of the four variables \(P\), \(V\), \(n\), or \(T\) can be considered unknowns to solve for, provided the other three are known.