posted by Caitlyn .
A cylinder containing 48g of nitrogen gas at room temperature is placed on a scale. The valve is opened and 12g of gas are allowed to escape. Assuming that the temperature of the cylinder remains constant, how does the pressure change?
12/48 = 0.25 or 25% so the pressure will be reduced by 25% (or another way to say it is that the pressure will be 75% of the original).
So if the original P = 1 atmosphere, the new P would be 0.75 atm or if the original P = 2 atm the new P = 1.5 atm etc.