Question

Ammonium perchlorate is the solid rocket fuel used by the U.S. Space Shuttle. It reacts with itself to produce nitrogen gas , chlorine gas , oxygen gas , water , and a great deal of energy. What mass of oxygen gas is produced by the reaction of 2.83 g of ammonium perchlorate? Round your answer to 3 significant digits.

Answer 1

The balanced chemical equation is given as

2 NH₄ClO₄ (s) --------> N₂ (g) + Cl₂ (g) + 2 O₂ (g) + 4 H₂O (l)

As per the balanced stoichiometric equation,

2 moles NH₄ClO₄ = 2 moles O₂.

The atomic masses are

N: 14.007 u

H: 1.008 u

Cl: 35.453 u

O: 15.999 u

The gram molar mass of NH₄ClO₄ = (1*14.007 + 4*1.008 + 1*35.453 + 4*15.999) g/mol = 117.488 g/mol.

Mole(s) of NH₄ClO₄ corresponding to 2.83 g ammonium perchlorate =

(mass of ammonium perchlorate)/(molar mass of ammonium perchlorate)

= (2.83 g)/(117.488 g/mol)

= 0.02409 mole.

As per the stoichiometric equation,

0.02409 mole ammonium perchlorate = (0.02409 mole ammonium perchlorate)*(2 moles O₂)/(2 moles ammonium perchlorate)

= 0.02409 mole O₂.

The gram molecular mass of O₂ = (2*15.999) g/mol = 31.998 g/mol.

Therefore, the mass of O₂ produced = (moles of O₂)*(molar mass of O₂)

= (0.02409 mole)*(31.998 g/mol)

= 0.7708 g ≈ 0.771 g (ans, correct to three sig. figs).