How Do You Calculate Final Pressure in a Compressed and Cooled Ideal Gas?

[dnl65078]

Homework Statement

A sample of an ideal gas is both compressed and cooled. The given variables for the gas are: P1 = 90.0 kPa, V1 = 0.0800 m3, V2 = 0.0400 m3, T1 = 300. K, T2 = 260. K. Calculate the final pressure.

Homework Equations

PV=nRT
P1 V1 /T1 = P2V2 / T2

The Attempt at a Solution

P2 = T1 V / P1V T2
= 299*1.29 / 1.40 *315 * 1.29
P2 = 0.67 atm

***I thought i was doing this right, but webassign says it's wrong... please advise?

 

[willem2]

P1 V1 /T1 = P2V2 / T2

The Attempt at a Solution

P2 = T1 V / P1V T2

this is wrong already. mulitply your first equation by T2 and then divide by V2.

299*1.29 / 1.40 *315 * 1.29
P2 = 0.67 atm

What are all those numbers that aren't in the problem statement?
I suppose the answer should be in kPa as well.