To determine the pressure at which a balloon filled with 5.0 L of helium will burst, it is essential to apply the ideal gas law and consider the changes in pressure and volume as the balloon rises. Initially, the balloon is filled with 0.5 L of helium at 1 atm. As the balloon ascends, the external pressure decreases, causing the volume of the gas to expand. The key is to use the relationship defined by Boyle's Law, which states that pressure and volume are inversely related when temperature is constant. By calculating the volume expansion at lower pressures, one can find the critical pressure point where the balloon reaches its maximum capacity of 5.0 L before bursting. It is crucial to show the calculations and rationale behind the gas law application to arrive at the correct bursting pressure.