Final answer:
The symbol 'R' in the ideal gas law equation PV = nRT refers to the constant known as the gas constant or the universal gas constant.
Step-by-step explanation:
In the ideal gas law equation, PV = nRT, the symbol R refers to a constant known as the gas constant or the universal gas constant. This constant allows us to use the equation to relate pressure (P), volume (V), the number of moles of gas (n), and temperature (T) in Kelvin.
The most commonly encountered values for R are 0.08206 L atm mol⁻¹ K⁻¹ and 8.314 kPa L mol⁻¹ K⁻¹, depending on the units used for pressure and volume.