How many moles is 14.5cm^3 of platinum?

Question

How many moles is 14.5cm^3 of platinum? The density of platinum is 21.45 g/cm^3.

Help? (:

Answer 1

You have 14.5 cubic centimeters of platimum. The density ρ of platinum is about 21.4 grams / cubic centimeter, so you have

m = ρ V = ( 21.4 grams / cc ) ( 14.5 cc ) = 310.3 grams.

The gram-molecular weight of platinum is about 195 grams / mole, so you have

310.3 grams / 195 grams / mole = 1.59 moles of platinum.