Answer
Molecular formula of phosphorous is P4.
Work Step by Step
from Ideal gas law: PV = nRT
P = 16 kPa (0.157908 atm)
R: gas constant (0.0821 L-atm / mole-K)
T: gas temperature in Kelvin (373.15)
, but n = m/M .........m: is mass of gas........... M: molar mass of gas
PV = (m/M) RT
MPV =mRT ..................... M= (m/V)(RT/P)
m/V = d, while d is density of gas (mass/volume)
so M = (dRT)/P
= 0.6388 × 0.0821 × 373.15 / 0.157908
= 123.9 g
n of gas = Mass of gas / Molar mass of P (30.97)
= 123.9 /30.97
= 4
