chemistry stoichiometry

Question

If in the double replacement reaction of excess iron(II) phosphate with 24.69 kilograms of aluminum nitrite the products are iron(II) nitrite and aluminum phosphate, how many particles of iron(II) nitrite produced?

Answer 1

While it's unclear what is being meant by the term "particles", if we assume it refers to formula units (molecules), we have a simple stoichiometry problem. The 1st step in any stoic problem is to write a balanced equation, which would be as follows:

Fe₃(PO₄)₂ + 2 Al(NO₃)₂ → 3 Fe(NO₃)₂ + 2 AlPO₄

Next, since we're trying to determine the NUMBER of 'particles' we will use Avogaro's Number for our starting ratio:

(6.022 x 10²³ particles Fe(NO₃)₂/1 mol Fe(NO₃)₂) (3 mol Fe(NO₃)₂/2 mol Al(NO₃)₃) (1 mol Al(NO₃)₂/26.98 g Al(NO₃)₃) 24690g Al(NO₃)₃ = 8.266 x 10²³ particles of iron (II) nitrate