Final answer:
Using Boyle's Law, the final volume of a helium balloon rising to a height of 6.5 km with the pressure dropping to 0.40 atm and constant temperature is found to be 1.375 liters.
Step-by-step explanation:
To determine the final volume of an inflated helium balloon that rises from sea level (1.0 atm) to a height of 6.5 km (0.40 atm) while assuming constant temperature, we can use Boyle's Law. Boyle's Law states that the pressure and volume of a gas are inversely proportional when the temperature is held constant (P1V1 = P2V2). As per the question, we have the initial volume V1 = 0.55 L and pressure P1 = 1.0 atm, and the final pressure at 6.5 km altitude P2 = 0.40 atm.
To solve for the final volume V2, we rearrange Boyle's Law as V2 = (P1V1) / P2. Hence, V2 = (1.0 atm * 0.55 L) / 0.40 atm. Calculating this gives us V2 = 1.375 L.
Therefore, the final volume of the balloon at 6.5 km is 1.375 liters.