The hydrocarbon naphthalene calculations

The hydrocarbon naphthalene was frequently used in mothballs until recently, when it was discovered that human inhalation of naphthalene vapors can lead to haemolytic anemia. Naphthalene is 93.71% carbon by mass, and a 0.260-mole sample of naphthalene has a mass of 33.3 g. What is the molecular formula of naphthalene? (Naphthalene only contains carbon and hydrogen.)
its C10H8

This compound works as a pesticide in mothballs by sublimation of the solid so that it fumigates enclosed spaces with its vapors according to the following equation.naphthalene(s) naphthalene(g) K = 4.29 ✕ 10−6 (at 298 K)

If 2.85 g of solid naphthalene is placed in an enclosed space with a volume of 5.15 L at 25°C, what percentage of the naphthalene will have sublimed once equilibrium has been established?

sol.
Naphthalene (s) Naphthalene(g) ; K = 4.29 x 10^-6

Molar mass of naphthalene = 128 g/mol

Initial number of moles of naphthalene = 2.85 g /128 g/mol

                           = 0.0223 mol

Let x moles of Naphthalene is sublimed and develop an ICE table 

      Naphthalene (s) Naphthalene (g)

I      0.0223 mol                          0

C          -x                                    x

E       0.0223-x                            x

K = [ Naphthalene (g)] / [Naphthalene (s)]

4.29 x 10^-6 = x / 0.0223-x

by solving , x = 9.6 x 10^-8 mol

hence ,percent of naphthalene sublimed at the equilibrium

           = (9.6 x 10-8 mol / 0.0223mol)*100

                       = 4.3 x 10^-4%

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