Question

6 hematite (iron ore) weighing 70.7 g was placed in a flask whose volume was 53.2 ml. the flask with hematite was then carefully filled with water and weighed. the hematite and water weighed 109.3 g. the density of the water was 0.997 g/cm3 . what was the density of the hematite?

Answer 1

The density of hematite ore is 4.78 g/cm³.

Let the mass of the ore be m₁ , the volume of the flask V, total mass of water and ore M, mass of water be m₂, density of ore ρ₁ and the density of water be  ρ₂.

Density of a substance is defined as the mass per unit volume.

The mass of water in the flask is given by,

$M-m_1= (109.3 g)-(70.7 g)=38.3 g$

Calculate the volume V₂ of the water in the flask.

$V_2=\frac{m_2}{\rho_2} =\frac{38.3 g}{0.997 g/cm^3} = 38.4cm^3$

Calculate the volume V₁occupied by the ore in the flask.

$V_1=V-V_2=(53.2 cm^3)-(38.4cm^3)=14.8cm^3$

1 ml is equivalent to 1 cm³.

Calculate the density of the ore.

$\rho_1=\frac{m_1}{V_1}=\frac{70.7 g}{14.8 cm^3} = 4.78g/cm^3$

The density of the hematite ore is found to be 4.78 g/.cm³