# A balloon is filled with 73 Lof air at 1.3 atm pressure. What pressure is needed to change the volume to 43 L?

May 12, 2017

We use old Boyle's Law........and get approx. ${P}_{2} = 2 \cdot a t m$.
For a given quantity of gas, pressure is inversely proportional to pressure: $P \propto \frac{1}{V}$. And so $P V = k$, and thus ${P}_{1} {V}_{1} = {P}_{2} {V}_{2}$.
We solve for P_2=(P_1V_1)/(V_2)=(73*Lxx1.3*atm)/(43*L)=??atm.