Determine the number of moles of gas contained in a 1.25 L container at 25 degrees Celsius and 800 torr

You would have to use the ideal gas law: PV = nRT where,

P = pressure

V = volume

n = moles

R = universal gas constant for a specific pressure (in this case it's 62.364 torr)

T = temperature in Kelvin

First, convert Celsius to kelvin by adding 273 to 25, which gives you 298K

Now plug in your variables to find n:

(800 torr) (1.25 L) = n (62.364) (298K)

1000 = 18584.472n

Now divide 1000 by 18584.472 to get n:

1000/18584.472 = 0.054 moles