# Question 78c76

Jun 17, 2016

1.430 × 10^6color(white)(l) "g Fe"_2"O"_3#

#### Explanation:

1. Find the number of moles of Fe you need to make by dividing mass by atomic mass.

Since you need grams at the end, convert kilograms to grams first.

1000 kg = 1 000 000 g.

Divide by 55.85 g/mol Fe.

1 000 000 g ÷ 55.85 g/mol Fe = 17 905 mol Fe.

2. The ratio of $F {e}_{2} {O}_{3}$ to $F e$ is 2:4, so you'll need half as much $F {e}_{2} {O}_{3}$ as $F e$.

${\text{17 905 mol Fe" ÷ "2 mol Fe/mol Fe"_2"O"_3 = "8952.6 mol Fe"_2"O}}_{3}$
3. Multiply this number by the formula mass of $F {e}_{2} {O}_{3}$:
${\text{8952.6 mol Fe"_2"O"_3 × "((55.85×2)+(16.00×3)) g/mol Fe"_2"O"_3 = 1.430 × 10^6 "g Fe"_2"O}}_{3}$.