How many molecules of nitrogen gas are in a 5.20 l vessel at 136°c and 0.43 atm?

Data:
P = 1 atm
V = 5.20 L
n = ?
R = 0.082 for pressures in atmosphere (atm)
T = 136ºC 
The temperature to be used in the equation will always be in Kelvim (K), so if it is in degrees Celsius (° C) it is necessary to convert. To do this simply add the value 273.
TK = TºC + 273
TK = 136 + 273
TK = 409

Formula: (General Equation of Perfect Gases)

P*V = n*R*T
1*5.20 = n*0.082*409
5.20 = 33.538n
33.538n = 5.20

of nitrogen molecules

Note: One mole is the amount of matter in a material system containing  particles (elemental entities).

Therefore:

Number atoms in 1 mol of molecules of N2 = 6.02*10²³ * 2 = 12.04*10²³

1mol ---------------- 12,04*10²³ 
0.15 mol ---------------- x 

x = 0.15 * 12,04*10²³ 
x ≈ 1.8*10²³ atoms in 1 mole of N2 molecules.

Particle exchange energy though elastic collision , hope this .