Answer:
-0.625 atm
Explanation:
We need both volumes to be the same unit... sooooo....
750 mL = 0.750 L
And STP means the pressure is at 1 atm....
V1 = 0.750 L
V2 = 2.00 L
P1 = 1 atm
And we will use this equation (Boyle's law) to get where we need to go:
P1*V1 = P2*V2
And we plug in everything:
(1 atm)*(0.750 L) = P2*(2.00 L)
0.750 L*atm = P2*(2.00 L)
[divide by 2.00 L on both sides, making L cancel out and leave us with atm as the units]
P2 = 0.375 atm
BUT!! We are not done yet!
The question asked the CHANGE in pressure, not the final pressure. Sooooo.....
P2 - P1 = change in P
0.375 - 1 = -0.625 atm
Change in P = -0.625 atm
Hopefully I did that right!!
