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Magnetite has the chemical formula Fe3O4, which means it consists of three iron atoms (Fe) and four oxygen atoms (O). The oxidation state of oxygen is -2. To determine the overall charge of the compound, we use the formula nFe + mO = 0, where n is the oxidation state of iron and m is the count of each element. For Fe3O4, the oxidation state of iron (n) can be calculated as \(3n + 4(-2) = 0\). Similarly, hematite has the chemical formula Fe2O3, which means it contains two iron atoms and three oxygen atoms. The oxidation state of iron (n) can be calculated as \(2n + 3(-2) = 0\).

Using the equations above, we solve for the oxidation states of iron in magnetite and hematite: For magnetite (Fe3O4): \(3n + 4(-2) = 0 \Rightarrow 3n - 8 = 0 \Rightarrow n = \frac{8}{3}\). For hematite (Fe2O3): \(2n + 3(-2) = 0 \Rightarrow 2n - 6 = 0 \Rightarrow n = 3\). The oxidation states of iron in magnetite and hematite are \(\frac{8}{3}\) (approximately 2 and 3) and 3, respectively.

Ferrimagnetic materials exhibit magnetic properties in which the magnetic moments of atoms or ions on different sublattices are aligned in opposite directions and their magnitudes are unequal. Antiferromagnetic materials have magnetic moments that are aligned oppositely but are equal in magnitude, resulting in a net magnetic moment of zero. Magnetite, with the mixed oxidation states of approximately 2 and 3, is more likely to be ferrimagnetic. This is because the difference in the oxidation states results in unequal magnetic moments, leading to a net magnetic moment in magnetite. Hematite, with the same oxidation state of iron (3) across its lattice, is more likely to be antiferromagnetic due to the equal magnetic moments leading to a net magnetic moment of zero.

Since magnetite is ferrimagnetic and hematite is antiferromagnetic, it is possible to use magnetic fields for their separation. The magnetite with its net magnetic moment will be attracted or repelled by magnetic fields, whereas the hematite with its net magnetic moment of zero will not respond to magnetic fields significantly. Thus, the difference in the magnetic properties of these iron oxides can be exploited to separate them by applying magnetic fields. To summarize: (a) Magnetite (Fe3O4) is more likely to be ferrimagnetic due to its mixed oxidation states of iron, resulting in unequal magnetic moments. (b) Yes, it is possible to use magnetic fields to separate magnetite and hematite due to their differing magnetic properties.