Density is a ratio. Density indicates how much matter is packed into a given amount of space. For example, in a gold object, a whopping 19.3 grams of gold is packed into every cm³; that is, gold has a density of 19.3 g/cm³. Compare gold, which is very dense, to a lightweight metal like aluminum. The density of aluminum is just 2.7 g/cm³, meaning that each cm³ of aluminum has a mass of just 2.7 grams. Champion cyclist Lance Armstrong could probably afford it, but he wouldn't want to ride a bicycle with a gold frame. The mass of the bike would slow him down considerably!

 

In solving these practice problems, remember that one mL is equivalent to one cm³ of volume.

 

1 mL = 1 cm³