Question

How can density be used to identify substances?

Answer 1

Hint Density is the ratio of mass and volume of a substance and it is different for all substances. So, by knowing the density we can predict the nature of the substance.

Complete step by step solution:
In order to answer our question, we need to know what density actually is. Density is a property of a substance which measures how viscous or strong the substance is. If a substance has more density, it means that more atoms of it are occupied in a given closed space, which means it is more closely packed. In order to calculate the density of a substance, we have to divide the substance’s mass with its volume. Mathematically, $density=\dfrac{mass}{volume}$ and density has the SI unit of $kg\,{{m}^{-3}}$.
In other words, density can be said as a ratio, which is different for different substances. For example, density of water is $997\,kg\,{{m}^{-3}}$ and the density of mercury is $13600\,kg\,{{m}^{-3}}$. This means that in a volume of $1{{m}^{3}}$, the mass of water is 997 kilograms and that of mercury is 13600 kilograms. This means that mercury occupies more mass and has more number of atoms than that of water, for the same volume occupied.
The order of density of states of matter follow as :${{d}_{solid}}>{{d}_{liquid}}>{{d}_{gas}}$, as solids are most closely bound and gases are most freely bound. Hence, by knowing the density, we can compare two different materials and by seeing the density chart, we can also find out which material it is. This is how we identify substances using density.

NOTE: Density can also be used to predict which object will sink. For example, mercury will sink in water as it has more density, but oil has lesser density than water, so oil will float on the surface of water.