Question

*At 25 °C, gas in a rigid cylinder with a movable piston has a volume of 145 mL and a pressure of 125 atm. Then, the gas is compressed to a volume of 80mL What is the new pressure of the gas if the temperature is at 30°C?

Answer 1

Pressure will increase by the direct ratio of the volume change. Therefore, since volume changes from 145 to 80, pressure will go up by the ratio change 145÷80 times the original pressure 125 kPa. Sure, you can use the more complicated gas law equation PV = nRT but we are only varying volume so the question boils down to the change in one simple variable.

Putting them together we have: 145÷80 x 125 = 226.5625 or just 226 kPa since the accuracy of the figures and the equation are not great.