Question

2.38g of uranium was heated strongly in a current of air the resulting weight of the compound was 2.806g . Determine the empirical formula of the oxide.

Answer 1

Mass of oxygen that combined with uranium = 2.806 - 2.38
                                                                       = 0.426
Moles of oxygen = 0.426/16 = 0.026625
Moles of uranium = 2.38/238 = 0.01

Mole ratio: Oxygen = 0.026625/0.01 = 2.66 ≈ 2
                  Uranium = 0.01/0.01 = 1

The formula of Uranium oxide is UO2