Hey there!
Assuming the volume of the cylinder is 1 L.
Given, T=25 = 298K
As per the Dalton's law, total P = PNe + PAr ...where PNe = partial pressure of Ne and PAr = partial pressure of Ar.
PV = nRT
total P = (total moles)* (0.082057 L atm mol-1K-1 * 298)/1 = 5*0.082057*298 = 122.27 atm.
PNe = mole fraction of Ne * total P = (2/5)*122.27 = 48.908 atm
PAr = mole fraction of Ar * total P = (3/5)*122.27 = 73.362 atm
Total pressure is 122.27 atm
Ne pratial pressure = 48.908 atm
Ar prtial pressure = 73.362 atm
