Work Done by an Ideal Gas in Isothermal Expansion

Consider a closed system containing an ideal gas undergoing an isothermal expansion at a constant temperature of 300 K. The gas expands from a volume of 1 liter to 3 liters against an external pressure of 1 atmosphere. Calculate the work done by the gas during this expansion. Assume that R, the universal gas constant, is 0.0821 L·atm/(mol·K) and that there is 1 mole of gas in the system.

To find the work done by the gas, you can use the formula: W = -P_ext * ΔV, where ΔV is the change in volume, and P_ext is the external pressure.