Question

The mineral hematite is ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$. Hematite ore contains unwanted material called gangue in addition ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$. If 5.0kg of ore contains 2.78kg of Fe, what is the percentage purity of ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$

Answer 1

: An ore is a mixture of minerals, metals, and impurities that occur naturally and from which metal or minerals can be extracted economically. And Hematite is the most preferred source of iron in India Now to calculate the purity in 5Kg of ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$, first try to know the amount of Fe present in ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$

Complete step by step solution:
First, we will try to calculate the amount (or percentage) of Fe present in ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$, by using the concept of molecular mass,
Molecular of the mass of ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$ = 160g
The percentage of Fe present in ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$;
$\Rightarrow$ $\dfrac{{111.6}}{{160}} \times 100$ = 69.75%
[since the mass of one Fe = 55.8 and there are two Fe atoms present in ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$, $\Rightarrow$ the mass of 2Fe = 55.8 $\times$ 2 = 111.6g ]
$\therefore$ 69.75% of Fe is present in ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$
Now according to the question, the mass of Fe present is 2.78 Kg which means 69.75%
$\Rightarrow$ $\frac{{2.78}}{{69.75}} \times 100$ = 3.98g
So, the percentage purity ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$ is $\frac{{3.98}}{5} \times 100$ = 79.71%
Hence, the percentage purity of 5Kg of ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$ which contains 2.78 Kg of Fe = 79.71%

Additional information: Gangues are the particles of impurity having different physical properties than ore, this impurity can be easily separated using their difference in physical properties. E.g., magnetic behavior, gravitation forth formation (usually for Sulphur ores)

Note: While calculating the mass percentage remember to calculate only the mass percentage of the required metal. For example, Hematite ore is used for the extraction of Iron metal, hence we have only, calculated the percentage amount of Fe present in ${\text{F}}{{\text{e}}_2}{{\text{O}}_3}$, the three oxygen atoms can be reduced to give the required metal.