At what temperature will 2.5 mol nitrogen gas exert a pressure of 10.0 atm in a 2.0-L container?

The answer to your question is T = 97.6 °K

Explanation:

Data

Temperature = T = ?

number of moles = n = 2.5

Pressure = P = 10 atm

Volume = V = 2 l

Constant of ideal gases = 0.082 atm l / mol°K

Process

1.- Write the formula of the ideal gas law

         PV = nRT

-Solve for T

          T = PV / nR

2.- Substitution

           T = (10 x 2) / (2.5 x 0.082)

3.- Simplification

           T = 20 / 0.205

4.- Result

           T = 97.6 °K

that's what i got you can count the number of atoms