Answer: -40
Explanation: Percent error is calculated by subtracting the value you actually recieved from the literature value (175 in your case) SO your answer should be 135-175=-40.
The first option is the correct.
Since we know the mass of one atom of Fe is 56 and that of Cl2 atoms is 71 (one atom has 35.5 mass) hence both of them will be consumed
1. Convert 135g Fe2O3 to moles, divide by 2, and multiply the resulting number by the molar mass of Al
