How can density be used to identify substances?
You can identify an unknown substance by measuring its density and comparing your result to a list of known densities.
Density = mass/volume. Assume that you have to identify an unknown metal. You can determine the mass of the metal on a scale. You can determine the volume by dropping the object into a graduated cylinder containing a known volume of water and measuring the new volume. You divide the mass by the volume and compare the density to a list of known densities.
A metal bolt with a mass of 99.7 g is dropped into a graduated cylinder containing 50.0 cm³ of water. The new volume reads
72.1 cm³. Identify the metal.
V = 72.1 cm³ - 50.0 cm³ = 22.1 cm³
Now you compare your density with a list obtained from your instructor or from an on-line source such as
What metal was your bolt made of?