Hello all,

I have a few questions to which I thought I had the answer, but they're considered wrong by an answer sheet.

First question is,

1) A tightly sealed 5.0-L flask contains 781 mm Hg of Ar at 19 C. The flask is heated until the pressure is doubled. What is the temperature of the gas?

First, I determined that I will use Gay-Lussac's law in which I will be solving for T2. The equation will be arranged to T2=P2T1/P1. My arithmetic came out

T2= (1562*19)/781. Units cancel leaving Celcius. My final answer is 38 celcius.

The answer key provided states that the answer is 311C, what gives? I even tried to solve with the constant of volume, but the answer works out to be the same...

Thanks,

Bobby