Question

Give an example in which density is used to identify the substance composing an object. Would information in addition to average density be needed to identify the substances in an object composed of more than one material?

Short answer

Every material has a unique density, so any substance can be identified using it.

Step-by-step solution

Defining density

Different materials exhibit different densities. So, density is a characteristic property that identifies a material or the composed substance in an object. Density is the mass of a body per unit volume. Mass and volume of an object can be manually measured and, thus, density can be calculated. So material identification can be done.

Example

Consider an example in which density is used to identify the substance in the object. If we want to confirm that the substance contained in a bangle is gold, we first measure the mass and volume of the bangle. To measure the volume, dip the bangle in a container full of water. Dispersedamount of water will give the volume of the bangle. Calculate the density with the measured volume and mass.

If the density is equal to 19.32 10³ Kg/m³, we can confirm that the bangle is composed of gold. Because it is the unique density of gold. Likewise, it is possible to identify the material of various objects.

Finding whether all materials present in an object can be identified by knowing average density.

The average density of a material won’t be enough to identify the substance present in an object composed of several materials. Because average density is the ratio of the sum of all materials' mass to the sum of all materials' volume present in the mixture, So, here we require the individual mass and volume of the particular material present in the object. Somehow, the average density will be ranged in between the individual densities of the material present in the object.

Thus, density can be used to identify substances present in an object, but we couldn’t find the individual components present in an object if we only knew the average density of the object.