How do you determine the volume if 1.5 atm of gas at 20° C in a 3.0 L vessel are heated to 30° C at a pressure of 2.5 atm?
?? The volume is presumably constant..........
The problem has not been properly specified. You could have specified a gas in a PISTON, whose volume would decrease with increased pressure, and increase with increased temperature.
For such a system, we would use the