Physics: Expansion at constant pressure

[FutureE'neer]

Homework Statement

An unknown number of moles of an ideal monoatomic gas expand reversibly from Vi = 2.30 m3 to Vf = 3.10 m3, at a constant pressure of 1.71 atm and an initial temperature of 300 K.
Find the number of moles of gas.
Find the final temperature of the gas K.
Calculate the work done by the gas.

Homework Equations

I'm using PV=nRT

The Attempt at a Solution

Converting the pressure in atm to N/m^2 and m^3 to L. I'm using the initial volume for V, 8.315 for R and the initial temp in K and solving for n. I keep getting the same answer and it is coming up wrong. Please help!

 

[Clever-Name]

Write out all the units during your calculation. Do the units make sense in the end? Also, this isn't advanced physics.