In PV = nRT, what does R represent?

In PV = nRT, what does R represent?

• A. The gas constant
• B. The rate constant
• C. The universal gravitational constant
• D. The molar mass of the gas

Answer: (A)

R is the gas constant, a proportionality constant that makes the ideal gas law work across different units and meaningfully connect pressure, volume, temperature, and amount of substance. It sets the scale so PV = nRT holds for any ideal gas when you use consistent units. In SI units it’s about 8.314 J/(mol·K); in liter-atm units it’s about 0.0821 L·atm/(mol·K). It’s not the rate constant from kinetics, nor the gravitational constant, nor the molar mass of a particular gas. The constant serves as a universal bridge between the macroscopic state variables and the amount of substance.

R is the gas constant, a proportionality constant that makes the ideal gas law work across different units and meaningfully connect pressure, volume, temperature, and amount of substance. It sets the scale so PV = nRT holds for any ideal gas when you use consistent units. In SI units it’s about 8.314 J/(mol·K); in liter-atm units it’s about 0.0821 L·atm/(mol·K). It’s not the rate constant from kinetics, nor the gravitational constant, nor the molar mass of a particular gas. The constant serves as a universal bridge between the macroscopic state variables and the amount of substance.