Question

What is the mass of $25mL$ of a liquid if its density is $1.25g.m{L^{ - 1}}$ ?

Answer 1

Hint: The amount of matter in a liquid or an object is measured by its mass. A substance's or object's volume is the amount of three-dimensional space it takes up.

Complete step-by-step answer:
Density is the mass of a material substance per unit volume.
To find the mass of the liquid, we have to use the formula:
$Density = \dfrac{{mass}}{{volume}}$

Usually, the unit of density of a liquid is measured in $g.m{L^{ - 1}}$, and the unit of density of a solid is measured in $g.c{m^{ - 3}}$
The unit of mass of a substance is measured in grams, $g$.
The unit of volume of a substance is measured in $mL$ or $c{m^{ - 3}}$.

From the question, we have the density of the liquid and the volume of the liquid. We have to find the mass of the liquid. The units of density and volume which are given in the question have proper units. So, we just have to rearrange the formula to obtain the mass of the liquid.

$Density = \dfrac{{mass}}{{volume}}$
Taking volume to the left-hand side of the equation, the volume gets multiplied by density.
$Density \times Volume = Mass$
$ \Rightarrow Mass = Density \times Volume$
Therefore, the mass of a liquid is the product of its density and volume.

We have the volume of the liquid equal to $25mL$ and the density of the liquid equal to $1.25g.m{L^{ - 1}}$
Substituting the values we get,
$\dfrac{{1.25g}}{{mL}} \times 25mL$
$ = 31g$

Therefore, the mass of the liquid is equal to $31g$

Note: The liquid element mercury, with a density of $13.5$ grams per cubic centimeter, is the densest liquid on Earth. The densest known solid at Earth's surface temperatures and pressures is the metallic element osmium, which has a density of $22$ grams per cubic centimeter, or more than $100$ grams per teaspoonful.