I posted this before a few hours ago without a reply yet but decided I would add more detail:

question
The nuclide 38cl decays by beta emission with a half life of 40min. A sample of .40 m of H38cl is placed in a 6.24 liter container. After 80 min the pressure is 1650 mmHg. What is temperature of container?

I have tried calculating the decay rate of the 38cl and then plugging into the formula pv =nrt but I do not get the answer, 300 k. Any help would be great.

I would think it would be like this:
.40 mol is .0258% Hydrogen
.40 mole is .974 CL38
.40 x .974=.3896 x half life .25=.0974 + mole of hydrogen .01032
=.1077
13.54/.1077= 125k but this isn't correct

The correct answer is 300K
anybody know how it was obtained?