Two 6.5 L flasks are joined by a 150 mL tube with a stop cock. If 0.25 moles of nitrogen are held in the left flask and the right flask is empty, what happens to the entropy of the system upon opening the valve between the flasks? 1. The entropy remains the same. 2. There is too little information to assess the change. 3. The entropy decreases. 4. The entropy increases.