The densities of gases a, b, and c at stp are 1.25 g/l, 2.86 g/l and 0.714 g/l, respectively. calculate the molar mass of each substance. identify each substance as ammonia (nh₃), sulfur dioxide (so₂), chlorine (cl₂), nitrogen (n₂) or methane (ch₄).

The  molar  mass  of    a, b and  c at  STP is calculated  as  below

At  STP  T  is always=   273 Kelvin and ,P= 1.0 atm 

by  use of  ideal  gas  equation  that  is  PV =nRT
n(number   of moles) = mass/molar mass  therefore  replace   n  in  the  ideal   gas  equation

that  is Pv = (mass/molar mass)RT
multiply  both side  by molar  mass  and  then  divide  by  Pv  to  make  molar mass the  subject of the  formula

that is  molar  mass =  (mass x RT)/ PV

 density is always = mass/volume

therefore  by  replacing  mass/volume  in   the equation  by  density the equation
molar  mass=( density  xRT)/P  where R  =  0.082 L.atm/mol.K

the  molar mass  for  a
= (1.25 g/l  x0.082 L.atm/mol.k  x273k)/1.0atm = 28g/mol

the molar  mass of b
=(2.86g/l  x0.082L.atm/mol.k   x273  k) /1.0  atm  = 64  g/mol

the molar  mass of c

=0.714g/l  x0.082  L.atm/mol.K  x273 K) 1.0atm= 16 g/mol

therefore  the 
   gas  a  is  nitrogen N2   since 14 x2= 28 g/mol
   gas b =SO2  since  32 +(16x2)= 64g/mol
  gas c =   methaneCH4  since  12+(1x4) = 16 g/mol

What? i don’t understand

Hello thereone of the following properties was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version. which property fits this description? answer: atomic mass  was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.