To what temperature in K must a variable volume container of helium gas be cooled to obtain a final volume of 0.182 L? The initial volume and temperature are 2.34 L and 314 K, respectively. The pressure and number of moles are fixed.

Question

You're supposed to us V1/T1=V2/T2, and I did that and got .001356, which isn't right. Can someone help please?

At a fixed temperature and number of moles of nitrogen gas, its volume and pressure are 368 mL and 668 torr, respectively. What is the final pressure in torr, if the final volume is 260 mL?

This is P1V1=P2V2. I got 1.244, which is also wrong. Why?

Thanks in advance!

Answer 1

(V1/T1) = (V2/T2)
(0.182/T) = (2.34/314)
Solve for T. I found about 24.
I think I figures out what you're doing and it isn't the way to solve these problems. You're dividing 2.34/314 = 0.00745 then multiplying by 0.185 to obtain 0.00136. There's nothing wrong with 2.34/314 = 0.00745 so you rewrite the equation as (0.185/T) = 0.00745. From there, however, it is T = (0.185/0.00745) = about 24.

P1V1 = P2V2
668*368 = P2*260
P2 = about 945 torr

I expect you are not punching the right keys at the right time. You can go through it step by step if you wish and I can show you where you're going wrong.

Answer 2

I knew it was something like that, but I couldn't figure it out. Thank you!