Question

The molecular mass of compound a is 168 g/mol. its empirical formula is c4h4s. find its molecular formula

Answer 1

heyy user ur answer..........

the molecular formula of the compound given as C4H4SC4H4S .The gram molecular mass can be calculated by adding the individual masses of all the constituent elements .so lets do that first

Empirical formula mass C4H4S=(4×12Carbon+(4×1)Hydrogen+(32)Sulphur Empirical formulamassC4H4S=(4×12)⏟Carbon+(4×1)⏟Hydrogen+(32)⏟Sulphur

EmpiricalformulamassC4H4S=84.EmpiricalformulamassC4H4S=84. we'll call this e.f.m

Grammolecularmass=168.Grammolecularmass=168.we'll call this g.m.m

Now, the common factor(C.fC.f) is given by the formula

C.f=g.m.me.f.mC.f=g.m.me.f.m

substituting the value of e.f.me.f.mandg.m.mg.m.m in the above equation we get

C.f=16884C.f=16884

C.f=2C.f=2

now the molecular formula is given by the formula

Molecularformula=C.f×(Empiricalformula)Molecularformula=C.f×(Empiricalformula)

therefore ,

Molecularformula=2×(C4H4S)Molecularformula=2×(C4H4S)

Molecularformula=C8H8S2Molecularformula=C8H8S2

The molecular formula of the compound is C8H8S2

hope this will help u@kundan