A sample of bismuth weighing 0.687 g was converted to bismuth chloride by reacting it first with HNO3, and then with HCl, followed by careful evaporation to dryness. The mass of the bismuth chloride obtained was 1.032 g. What is its empirical formula

BiCl₃

Explanation:

The molar mass of bismuth is 208.987g/mol. Thus, moles of 0.687g of Bi are:

0.687g Bi × (1mol / 208.987g) = 3.287x10⁻³ moles of Bi

The mass of Bismuth is bismuth chloride is also 0.687g. Thus, mass of chloride is:

Cl mass = 1.032g - 0.687g = 0.345g of Cl.

As molar mass of Cl is 35.45g/mol:

0.345g Cl ₓ (1mol / 35.45g) = 9.732x10⁻³ moles of Cl

Empirical formula is defined as the simplest ratio of atoms in a compound. Dividing each moles in the lower number of moles (3.287x10⁻³ moles)

Ratio of Bi: 3.287x10⁻³ moles / 3.287x10⁻³ moles = 1

Ratio of Cl:9.732x10⁻³ moles of Cl / 3.287x10⁻³ moles = 3

Thus, empirical formula is:

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-