An ideal gas is contained in a cylinder with a movable piston. The gas undergoes an isothermal expansion from a volume of 2 liters to 8 liters at a temperature of 300 K. If the initial pressure of the gas is \( 2 \times 10^5 \, \text{Pa} \), calculate the work done by the gas during this expansion. (Use \( R = 8.31 \, \text{J/mol·K} \))