How many molecules of n2 are in a 200.0 ml container at 780 mmhg and 135∘c?

By use of ideal gas equation PV = nRT where n is the number of moles, P = pressure, V = volume, R = gas constant (0.08206 L. atm / mol. k) ant T is the temperature,

to calculate the number of moles (n) = PV/RT

convert ml to L, that is 200/1000 = 0.2 L

convert mmHg to atm, that is 780mm hg x 1atm / 760 mm hg = 1.026 atm

convert temperature to kelvin, that is 135 + 273 = 408 k

n is therefore = (0.2 x 1.026) / (0.08206 x 408) = 6.129 x10^-3 moles

from avogadro constant 1moles = 6.02 x10^23 molecules what about 6.129 x10^-3 moles

= (6.02 x10^23) x (6.129 x10^-3) / 1mole = 3.69 x10^21 molecules