# A weather balloon has a maximum volume of 7.50 * 10^3 L. The balloon contains 195 L of helium gas at a pressure of 0.993 atm. What will be the pressure when the balloon is at maximum volume?

Approx. $0.03 \cdot a t m \ldots \ldots \ldots$
We use old $\text{Boyle's Law}$, ${P}_{1} {V}_{1} = {P}_{2} {V}_{2}$ at constant temperature.
And we solve for ${P}_{2} = \frac{{P}_{1} {V}_{1}}{V} _ 2 = \frac{195 \cdot L \times 0.993 \cdot a t m}{7.5 \times {10}^{3} L}$
$= 2.58 \times {10}^{-} 2 \cdot a t m .$