What is the correct form of the ideal gas equation?

What is the correct form of the ideal gas equation?

• A. PV^2 = nRT
• B. PV = nRT^2
• C. p = nRT / V^2
• D. pV = nRT

Answer: (D)

The relationship that connects pressure, volume, temperature, and amount of gas is the ideal gas law. In SI units it is pV = nRT, with p for pressure, V for volume, n for number of moles, R the gas constant, and T the temperature in kelvin. This form matches how the variables interact in real gases: at fixed n and T, increasing volume lowers pressure in inverse proportion; at fixed P and V, raising temperature increases pressure proportionally; at fixed P and T, increasing the amount of gas increases the volume proportionally. Putting these together gives pV ∝ nT, and the exact proportionality constant is R, so pV = nRT. Remember that the numeric value of R depends on the units you use (e.g., 8.314 J/(mol·K) in SI; 0.08314 L·bar/(mol·K) if you use liters and bar).

The relationship that connects pressure, volume, temperature, and amount of gas is the ideal gas law. In SI units it is pV = nRT, with p for pressure, V for volume, n for number of moles, R the gas constant, and T the temperature in kelvin. This form matches how the variables interact in real gases: at fixed n and T, increasing volume lowers pressure in inverse proportion; at fixed P and V, raising temperature increases pressure proportionally; at fixed P and T, increasing the amount of gas increases the volume proportionally. Putting these together gives pV ∝ nT, and the exact proportionality constant is R, so pV = nRT. Remember that the numeric value of R depends on the units you use (e.g., 8.314 J/(mol·K) in SI; 0.08314 L·bar/(mol·K) if you use liters and bar).