Question

What is the density of 5 litres of water having mass 5 kg?

Answer 1

Hint: The density of any substance is the measure of its mass per unit of volume. The density tells the mass that is contained in each unit of volume. The units of mass is in kg or g, while the volume will be taken in per meter cube, so litre will be converted to meter form the conversion factor that 1 L = 0.001 cubic meter.
Formula used:
Density = $\dfrac{mass}{volume}$

Complete answer:
Density of any substance is the measure of the mass of that substance in per unit volume of the substance. If a material has more dense mass and magnitude then, that substance will more likely to have less volume. So, the density of any substance is the mass that is composed per cubic volume. Therefore, the formula of density is mass upon volume. The density is measured in the unit g per cubic meter or kilogram per cubic meter.
We have been given the mass and volume of water for which density has to be calculated. The mass of water is 5 kg and the volume is 5 litres. So, first converting the volume into cubic meter we have,
1 L = ${{10}^{-3}}{{m}^{3}}$
So, 5 L = $5\times {{10}^{-3}}{{m}^{3}}$
Now using, density = $\dfrac{mass}{volume}$
Density = $\dfrac{5\,kg}{5\times {{10}^{-3}}{{m}^{3}}}$
Density = $1000\,kg/{{m}^{3}}$
So, the density of water is $1000\,kg/{{m}^{3}}$.

Note:
The fact that ice floats on water is due to the density. Ice due to its 3 – D structure has less density due to more volume in between its molecules. Therefore ice being less dense than water is able to float on water. While, the more dense substances tend to sink in water. The volume and mass of the water are nearly equal, which makes its density $1000\,kg/{{m}^{3}}$.