To solve this problem, we can use Boyle's Law, which states that the product of pressure and volume is constant at constant temperature. Mathematically, it can be expressed as:
P1 * V1 = P2 * V2
Where: P1 = Initial pressure V1 = Initial volume P2 = Final pressure V2 = Final volume
We are given the following information: P1 = 0.95 ATM V1 = 25 L V2 = 12.5 L
We need to find P2, the final pressure.
Using Boyle's Law equation, we can rearrange it to solve for P2:
P2 = (P1 * V1) / V2
Plugging in the values:
P2 = (0.95 ATM * 25 L) / 12.5 L
P2 = 1.9 ATM
Therefore, the pressure needed to reduce the volume of the oxygen gas to 12.5 L is 1.9 ATM.