Patrick studies a mixture of helium and argon of one liter at 25 degrees celsius
ID: 952225 • Letter: P
Question
Patrick studies a mixture of helium and argon of one liter at 25 degrees celsius and 1 atm pressure in a cylinder. He brings the cylinder in contact with liquid nitrogen (66K) at which a small amount of a white substance deposits on the walls of the cylinder and the volume of the gas reduced to 220mL. The pressure remains constant. Neglecting the volume of the solid formed, what was the partial pressure of the helium at 25 degrees celsius? What is the white powder?
BP of helium is 4.2K and that of argon is 87.45K. Melting point of argon is 90.15K.
Explanation / Answer
P1V1 = P2V2 [at constant temp.and no. of moles]
P1 = 1 atm.
V1 = 1 lt
V2 = 220 ml = 0.22 lt
P2 = ?
P2 = 1*1/0.22 = 4.54 atm.
partial pressure of the gas is 4.54 atm.
the white powder is may be Helium because its BP is 4.2 K which is less than liquid nitrogen temperature 66K