# PVT Relationships

db1
How do i calculate pressure?

P1 = 3atm ............. P2 = ?
V1 = 4 m3...............V2 = 2 m3(half original)
T1 = 300k...............T2 = 400

how do i calculate pressure when V2 changes?

Thanks for any help

skaboy607
You need to give a bit more on the problem? What fluid are you using?

db1
just says a quantity of gas

skaboy607
I'll assume that they want to use the ideal gas law to solve then.

db1
P2 = 8atm, im just not sure how to work it out

skaboy607
You have a gas at two states; lets call it state 1 and state 2.

Ideal gas law is pV=mRT where R is universal gas constant of 8314.

You have all the parameters for state 1 apart from the mass. Once you know this you will know all the parameters for state 2 apart from the pressure. Plug in the numbers and theres your answer.

db1
its just talking about the combined gas equation PV/T= constant

it isnt saying anything about m or R yet

skaboy607
Well then it is even easier!

PV/t=constant so for state 1, obtain an aswer (this is constant) then rearrange for V and plug in the values for state 2.

db1
have it now, thanks for your help