Answer: The gas constant \( R \) can be used in different forms depending on the units of pressure, volume, and temperature.
Explanation: The value of \( R \) is used in the ideal gas law \( PV = nRT \), where:
- \( R = 0.0821 \, \text{L} \cdot \text{atm} / (\text{mol} \cdot \text{K}) \) is used when pressure is in atmospheres (atm) and volume is in liters (L).
- \( R = 8.314 \, \text{J} / (\text{mol} \cdot \text{K}) \) is used when pressure is in pascals (Pa) and volume is in cubic meters (m³), as it relates to energy in joules.
Different contexts or unit systems will dictate which value of \( R \) to use.