Question

a. The emperical formula of sulfur chloride SCl. What is the molecular formula of the compounds if the molecular mass is 135 g mol. (recall that one mole of a substance contains 6.02x10^23 molecules of the substance)?

b. how many atoms of sulfur are in one mole of the compound?

c. how many atoms of chlorine are in one mole of the compound?

d. how many molecules comprise one mole of the compound?

Answer 1

(a) Given the emperical formula of sulfur chloride SCl

The emperical formula mass of SCl = At.mass of S + At.mass of Cl

                                                   = 32+35.5

                                                   = 67.5

Given molecular mass = 135 g

So n = molecular mass / emperical mass

       = 135 / 67.5

       = 2

So molecular formula = n(emperical formula)

                               = 2(SCl)

                               = S₂Cl₂

(b) 1 mole of S₂Cl₂ contains 2 moles of S

We know that 1 mole of any compound contains 6.023x10²³ (avagadro number) of atoms

So the number of S atoms = 2x60.23x10²³ = 12.046x10²³ atoms of S

(c) 1 mole of S₂Cl₂ contains 2 moles of Cl

We know that 1 mole of any compound contains 6.023x10²³ (avagadro number) of atoms

So the number of Cl atoms = 2x60.23x10²³ = 12.046x10²³ atoms of Cl

(d) 1 mole of S₂Cl₂ contains 6.023x10²³ (avagadro number) of molecules