Answer: The mass of ferrous sulfide required is 0.615 g
Step-by-step explanation:
To calculate the number of moles, we use the equation:
.....(1)
Given mass of iron (III) oxide = 0.56 g
Molar mass of iron (III) oxide = 159.7 g/mol
Putting values in equation 1, we get:

For the given chemical reaction:

By Stoichiometry of the reaction:
2 moles of iron (III) oxide is produced from 4 moles of ferrous sulfide.
So, 0.0035 moles of iron (III) oxide will be produced from =
of ferrous sulfide.
Now, calculating the mass of ferrous sulfide from equation 1, we get:
Molar mass of ferrous sulfide = 87.92 g/mol
Moles of ferrous sulfide = 0.007 moles
Putting values in equation 1, we get:

Hence, the mass of ferrous sulfide required is 0.615 g