Question

Na=14.31% S=9.97% H=6.62% and O=69.5% Calculate the Molecular formula of the compound if all the hydrogen in the compound is present in combination with oxygen as water of crystallization

Answer 1

HEY!!!!!



mole of Na = 14.31/23 = 0.622
mole of S = 9.97/32 = 0.311
mole of H = 6.22/1 = 6.22
mole of O = 69.5/16 = 4.34
relative number of atom of each atom :
for Na = 0.622/0.311 = 2
for S = 0.311/0.311 = 1
for H = 6.22/0.311 = 20
for O = 4.34/0.311 = 14
empirical formula = Na2SH20O14
empirical formula mass = 322
n*empirical formula mass = molecular formula mass
n*322 = 322
n = 1
it is given that all H is present as a H2O 
hence H20O10 = 10H2O
molecular formula = Na2SO4 .10H2O