When 80 grams of aluminum is reacted with excess chlorine gas, how many formula units of alcl3 are produced?

Al reacts with Cl2 and produces AlCl3. The balanced equation for the reaction is

2Al + 3Cl₂ → 2AlCl₃

Moles = mass / molar mass

Molar mass of Al = 27 g/mol

Mass of Al = 80 g

Hence moles of Al = 80 g / 27 g/mol = 2.96 mol

Stoichiometric ratio between Al and AlCl₃ is 1 : 1

Hence, moles of AlCl₃ = moles of Al = 2.96 mol

Hence, produced AlCl₃ is 2.96 mol 

Amount of AlCl₃ in formula units = moles of AlCl₃ x Avogadro's Constant

                                                        = 2.96 mol x 6.022 × 10²³ mol⁻¹

                                                        = 1.783 x 10²⁴

Hence, 1.783 x 10²⁴ of formula units of AlCl₃ are produced.

explanation:

two years ago, when picking flowers in the mountains back of yosemite valley, i found a book. it was blotted and storm-beaten; all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however; many of the inner pages were well preserved. and although all were more or less stained and torn, whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today; its granite pages have been torn and blurred by the same storms that wasted the castaway book.

two years ago, when picking flowers in the mountains back of yosemite valley; i found a book. it was blotted and storm-beaten, all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however, many of the inner pages were well preserved. and although all were more or less stained and torn; whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today, its granite pages have been torn and blurred by the same storms that wasted the castaway book.