Question

how many daL of bromine are in 15.7*10^22 molecules? (The density of bromine is 3.1 g/cm^3)

Answer 1

First we use avogadro's number to turn molecules into moles:

15.7 x 10²² molecules * (1 mol / 6.022 x 10²³ molecules) = 0.2607 moles of Br

Then we turn them into grams:

0.2607 moles of Br * (79.9 grams / mol) = 20.83 grams of Br

Then with density we turn them into volume:

20.83 grams of Br * (1 cm³ / 3.1 g) = 6.7196 cm³

We turn cubic centimeters to cubic meters:

6.7196 cm³ * (1 m / 100cm)³ = 6.7196 x 10^-6 m³

And then to liters:

6.7196 x 10^-6 m³ * (1000 L / 1 m³) = 0.0067 L

And finally to, I hope it is dL and not daL, deciliters:

0.0067 L * (10 dL / 1 L) = 0.0672 dL