In: Chemistry
A pure gas contains 81.71% carbon and 18.29% hydrogen by mass. Its density is 1.97 g/L
element % A.Wt relative number simple ration simplest ratio
C 81.71 12 81.71/12 = 6.8 6.8/6.8 = 1 1*3 = 3
H 18.29 1 18.29/1 = 18.29 18.29/6.8 = 2.68 2.68*3 = 8
The empirical formula = C3H8
The empirical formula mass = 12*3 + 8 = 44g/mol
molecular formula = ( empirical formula)n
At STP
molar mass = volume * density
= 22.4L/mole* 1.97g/L = 44g/mole
n = molar mass/empirical formula mass
= 44/44 = 1
molecular formula = (C3H8)1 = C3H8