Question

Consider the following reaction: 3Fe(s) + 4H₂O(g) ➞ Fe₃O₄(s) + 4H₂(g). To answer the following question: "How many moles of hot water vapor (steam) must react to produce 275 g of Fe₃O₄?" How many steps will it take to get the answer? *
4 points
1
2
3
4

Answer 1

Answer: 2

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$

$\text{Moles of} Fe_3O_4=\frac{275g}{233.5g/mol}=1.18moles$

$3Fe(s)+4H_2O(g)\rightarrow Fe_3O_4(s)+4H_2(g)$  

According to stoichiometry :

1 mole of $Fe_3O_4$ are produced by = 4 moles of $H_2O$

Thus 1.18 moles of $Fe_3O_4$ will be produced by=$\frac{4}{1}\times 1.18=4.72moles$  of $H_2O$

Mass of $H_2O=moles\times {\text {Molar mass}}=4.72moles\times 18g/mol=85.0g$

Thus 85.0  g of $H_2O$ will be required and 2 steps are required to get the answer.