Question

Burning a compound of calcium, carbon and nitrogen in oxygen generates calcium oxide (CaO), carbon dioxide (CO2) and nitrogen dioxide (NO2). A small sample gives 3.106 g CaO, 2.439 g CO2, and 5.097g NO2. Determine the empirical formula of the compound.

Answer 1

Answer:

CaCN₂

Explanation:

A compound of calcium, carbon and nitrogen CaₐCₓNₙ in oxygen will burning producing:

CaₐCₓNₙ + O₂ → aCaO + xCO₂ + nNO₂

Moles of the oxides CaO, CO₂, NO₂ are:

CaO: 3.106g ₓ (1 mole / 56.08g) = 0.0554 moles of CaO = moles of Ca

CO₂: 2.439g ₓ (1mole / 44g) = 0.0554 moles CO₂ = moles C

NO₂: 5.097g ₓ (1mole / 46g) = 0.111 moles NO₂ = moles N

Empirical formula is the chemical formula that represents the simplest ratio of elements in a compound.

Having as basis 0.0554 moles (The lower number of moles):

0.0554 moles Ca / 0.0554 = 1 Ca

0.0554 moles C / 0.0554 = 1 C

0.111 moles N / 0.0554 = 2N

Thus, the compound CaₐCₓNₙ  has as empirical formula:

Ca₁C₁N₂ = CaCN₂