Question

How do you calculate mass using density and volume?

Answer 1

Hint:Density is always defined as, it is the mass of that substance per volume. The density is generally measured for the pure liquids and solids and the standard equation for density is,$\text{density( }\!\!\rho\!\!\text{ )=}\dfrac{\text{mass(m)}}{\text{Volume(V)}}$

Complete answer:
So in the question we are asked to calculate the mass of the given sample if we are provided with the density and volume of the substance.
From the lower classes we are familiar with the terms like mass, volume and density.
We generally see the three combinations regularly in physics but it is also used in chemistry if we are dealing with pure substances like pure solid and liquid etc.
We generally compare and calculate values of density for the pure compounds since the density value of the pure compounds will help us to predict the different combinations of atoms possible and estimate various compositions of different kinds of mixture if the density of the pure compounds in the mixture are known.
The term mass is used to explain an amount or quantity of solute of substance present in a solution or the mass of the atoms present in the crystal lattice of the crystal structure. We generally related the mass and density terms while discussing solid state and volume while discussing the solutions in liquid states.
We have studied the standard definition for density ($\rho$) of a substance as density is the mass of the substance observed per volume of the substance.
So by definition we could say, $\text{Density}\left( \text{ }\!\!\rho\!\!\text{ } \right)\text{=}\dfrac{\text{Mass}\left( \text{m} \right)}{\text{Volume}\left( \text{V} \right)}$$\text{Mass}\left( \text{m} \right)\text{=density}\left( \text{ }\!\!\rho\!\!\text{ } \right)\text{ }\!\!\times\!\!\text{ Volume}\left( \text{V} \right)$
By altering the equation and writing the equation for mass, we will get,
$\text{Mass}\left( \text{m} \right)\text{=density}\left( \text{ }\!\!\rho\!\!\text{ } \right)\text{ }\!\!\times\!\!\text{ Volume}\left( \text{V} \right)$
$\text{m= }\!\!\rho\!\!\text{ }\!\!\times\!\!\text{ V}$
So by this equation we will get the mass of the substance. The unit generally used for representing mass is Kg, for density is grams per cubic centimeter ($g/c{{m}^{3}}$) or Kg per cubic metres ($Kg/{{m}^{3}}$).

Note:
We can find the number of moles if the solute if the molecular mass of the given compound is known. By dividing the obtained mass with the molecular mass of the substance we will get the number of moles of the solute.
$\text{Number}\text{of}\text{moles of solute=}\dfrac{\text{mass }\text{obtained}}{\text{Molecular}\text{mass}}$