How many moles of nitrogen we have at a temperature of 30 ºc, a pressure of 4.0 atm, and a volume of 4000.ml?

0.643 mol.

Explanation:

where, P is the pressure of the gas in atm (P = 4.0 atm).  

V is the volume of the gas in L (V = 4000 mL = 4.0 L).  

n is the no. of moles of the gas in mol (n = ??? mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K),  

T is the temperature of the gas in K (T = 30ºC + 273 = 303 K).

∴ n = PV/RT = (4.0 atm)(4.0 L)/(0.0821 L.atm/mol.K)(303 K) = 0.643 mol.