In an effort to sanitize his water, Beethoven knows that bromine can be used to purify water. If Beethoven has 2.12 x 1022 formula units of aluminum bromide are reacted with excess chlorine gas, how many milliliters of liquid bromine (density = 3.12 g/mL) are formed?

2.7 mL

Explanation:

The equation of the reaction is;

2AlBr3 + 3Cl2 > 2AlCl3 + 3Br2

Number of moles in 2.12 x 1022 formula units of aluminum bromide

1 mole of AlBr3 = 6.02 * 10^23 formula units

x moles = 2.12 x 1022 formula units

x = 2.12 x 1022 formula units  * 1 mole/ 6.02 * 10^23 formula units

x = 0.0352 moles of AlBr3

According to the reaction equation;

2 moles of AlBr3 produces 3 moles of Br2

0.0352 moles of AlBr3 produces 0.0352 moles  *  3 moles /2 moles

= 0.0528 moles of Br2

Mass of Br2 produced = 0.0528 moles of Br2 * 159.808 g/mol

Mass of Br2 produced = 8.44g

But density = mass/volume

volume = mass/density

volume of Br2 = 8.44 g/ 3.12 g/mL

volume of Br2 =  2.7 mL