Question

Calculate how many grams of Fe2O3 (molar mass 159.70 g/mol) are formed when 16.7 g of Fr react completely with O2.4 Fe + 3 O2—> 2 Fe2O3

Answer 1

The first step to solve this question is to convert the given amount of grams of Fe to moles using its molecular weight.

`16.7gFe\cdot(mol)/(55.845gFe)=0.3molFe`

According to the given reaction, 4 moles of Fe produce 2 moles of Fe2O3. Use this ratio to find how many moles of Fe2O3 are formed:

`0.3molFe\cdot(2molFe_2O_3)/(4molFe)=0.15molFe_2O_3`

Convert this amount of moles to grams using Fe2O3 molar mass:

`0.15molFe_2O_3\cdot(159.70g)/(molFe_2O_3)=23.9g`

It means that 23.9 grams of Fe2O3 are formed.