Question

On heating 4.89g of Fe3O4, how much Fe2O3 may be obtained?

Answer 1

Answer:

The amount of Fe2O3 obtained when 4.89 grams of Fe3O4 is heated is 5.092 grams.

Explanation:

Step 1 : write down the equation of the reaction.

We have :

4Fe3O4 + O2 —> 6Fe2O3

Step 2: Calculate the moles of Iron(iii) Oxide.

Molar mass of Iron(iii) Oxide :

= 56 × 3 + 16 × 4 = 232 grams/mol

Mass of Iron(iii)Oxide = 4.89

Moles = mass / molar mass

= 4.89/232 = 0.02108 moles

Step 3: Determine the mole ratio of Fe3O4 to Fe2O3.

The mole ratio is 4 : 6

Simplify to get = 2 : 3

For every 2 moles of Fe3O4 we have 3 moles of Fe2O3.

The moles of Iron(ii) Oxide will be given by :

3/2 × 0.02108 = 0.03162 moles

Step 4 : Determine the mass of Fe2O3.

Molar mass = 56 × 2 + 16 × 3 = 160 grams/mole

Mass = moles × molar mass

= 160 × 0.03162 = 5.0592 grams