Question

Calculate the mass of iron(III) oxide that contains a million iron atoms. Be sure your answer has a unit symbol if necessary, and round it to significant digits.

Answer 1

Answer: The mass of iron (II) oxide that contains a million iron atoms is $2.6\times 10^{-17}g$

Explanation:

We are given:

Number of iron atoms = A million = $1.0\times 10^6$

The chemical formula of the given compound is $Fe_2O_3$

It is formed by the combination of 2 iron atoms and 3 oxygen atoms.

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of particles

1 mole of iron (II) oxide will contain = $(2\times 6.022\times 10^{23})=1.2044\times 10^{24}$ number of iron atoms

We know that:

Molar mass of iron (II) oxide = 159.7 g/mol

Applying unitary method:

For $1.2044\times 10^{24}$ number of iron atoms, the mass of iron (II) oxide is 159.7 g

So, for $1.0\times 10^6$ number of iron atoms, the mass of iron (II) oxide will be $\frac{159.7}{1.2044\times 10^{24}}\times 1.0\times 10^6=2.6\times 10^{-17}g$

Hence, the mass of iron (II) oxide that contains a million iron atoms is $2.6\times 10^{-17}g$