ideal gases questions help?

I assume this is from the Zumdahl Zumdahl Chemistry 6th edition book, chapter five, page 234. I have this same homework and I think I have the answer. Disclaimer: I might be wrong!

First, you need to know this: 1 mol of an ideal gas at STP (1 atm and 0*C) occupies 22.4L.

So using the PV=nRT formula, 1atm(22.4L)=1(.082)(273.15)

(always convert *C to K before doing anything)

But! Your atm is not 1, it's 40. now you don't know how many L you have.

Set up: 40atm(xL)=1mol(.082)(273.15K)

solve and you get L= .5588575

Now all you have to do is plug in for parts A B and C

in A, convert to K then plug your numbers into PV=nRT. Your variable this time will be P and your T will change (because the question says so)

in B, do the same, but your variable will be T and P will change (because the problem says so.

in C, do the same as in B.

When you solve, check your answers. In mine, on (A) my pressure was slightly larger, which makes sense because there wasn't a large temp change. On (B) my temperature was much larger because there was a big pressure change. In (C) my temp was much lower because there was a lower pressure.

Hope this helped and hope I'm right (for both of our grades)

b. at what temperature would the pressure be 150 atm

use PV=nRT