The sample has 4 moles of gas and is kept at a temperature of 275 K. The volume is changed from 0.6 L to (3)0.6 L. What is the change in entropy, in liters atm per kelvin, if R = 0.082 L atm (K^-1) (mol^-1), a = 1.2 L^2 (atm)/(mol^2), and b = 0.07 L/mol?