Final answer:
The gas law that should be used for this problem is Boyle's Law, which states that the pressure and volume of a gas are inversely proportional when the temperature and the amount of gas remain constant. The gas law that should be used for this problem is A. P1V1 = P2V2.
Step-by-step explanation:
This equation is known as Boyle's Law, which states that the pressure and volume of a gas are inversely proportional when the temperature and the amount of gas remain constant. In this case, the initial pressure (P1) is 1.0 atm, the initial volume (V1) is 5.1 L, and the final pressure (P2) is 0.85 atm. To find the final volume (V2), we can rearrange the equation to solve for V2:
V2 = (P1 * V1) / P2
Substituting the given values into the equation:
V2 = (1.0 atm * 5.1 L) / 0.85 atm = 6.0 L
Therefore, the volume of the balloon would be 6.0 L once the pressure drops to 0.85 atm in the troposphere.