Answer
mass of oxygen = 22.54 g
Step-by-step explanation
Given:
4 Fe + 3 O2 = 2 Fe2O3
Mass of Fe203 = 75 g
Required: Mass of O2
We know:
Molar mass of Fe2O3 = 159,69 g/mol
Molar mass of O2 = 31.998 g/mol
Solution:
Step 1: Calculate the moles of Fe2O3
n = m/M where n is the moles, m is the mass and M is the molar mass
n = 75g/159,69 g/mol
n = 0.469 mol
Step 2: Use the stoichiometry to find the moles of O2
The molar ratio between Fe2O3 and O2 is 2:3
Therefore moles of O2 = 0.469 mol x (3/2) = 0.704 mol
Step 3: Find the mass of O2
m = n x M
m = 0.704 mol x 31.998 g/mol
m = 22.54 g