Density = (Mass/Volume)

You know the Mass and the Volume of your sample metal. You also know the density of aluminum. If you divide the mass of the sample metal by its volume and get 2.7g/cm^3 (the density of aluminum) than you have aluminum.

Densities are unique to each element, no 2 are the same (compounds may be different), this is why you can calculate somethings density to find out what it is.

Here is an example.

I have 1 gram of metal Y. This gram occupies 2 cubic centimeters of space. I wish to know its density.

Density of metal Y = (Mass of metal Y/Volume of metal Y)

Density of metal Y = (1g / 2cm^3)

Density of metal Y= ( .5g/cm^3 )

Therefore the density of metal Y would be .5g per cm^3 meaning that for every cubic centimeter of metal Y I would have half a gram of metal Y. This also means that for every half a gram of metal Y I would also have one cubic centimeter of metal Y.

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Some more related equations.

If Density = (Mass/Volume) than Volume = (Mass/Density) and Mass = (Density * Volume)

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