Question

Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel rocket motors. The reaction is given below. Fe2O3(s) + 2 Al(s) 2 Fe(l) + Al2O3(s) What masses of iron(III) oxide and aluminum must be used to produce 12.0 g iron? iron (III) oxide WebAssign will check your answer for the correct number of significant figures. 17.2 Correct: Your answer is correct. g aluminum WebAssign will check your answer for the correct number of significant figures. 2.98 Incorrect: Your answer is incorrect. g What is the maximum mass of aluminum oxide that could be produced?

Answer 1

Answer:

• 1. Iron(III) oxide: 17.2 g

• 2. Aluminum: 5.80 g

• 3. Aluminum oxide: 11.0g

Explanation:

1. Chemical reaction (given)

    $Fe_2O_3(s)+2Al(s)\rightarrow 2Fe(l) + Al_2O_3(s)$

2. Mole ratios

    $1molFe_2O_3(s):2molAl(s):2molFe(l):1molAl_2O_3(s)$

3. Convert 12.0g of iron to moles

• atomic mass of Fe: 55.845g/mol

• number of moles = mass in grams / atomic mass

• number of moles = 12.0g / 55.845g/mol = 0.215mol

4. Iron(III) oxide

• molar mass Fe₂O₃: 159.69 g/mol

• mole ratio: 1 mol Fe₂O₃ : 2 mol Fe

        $0.215molFe\times \dfrac{1molFe_2O_3}{2molFe}\times 159.69g/mol=17.2g$

5. Aluminum

• atomic mass Al: 26.982g/mol

• mole ratio: 2 mol Al : 2 mol Fe

        $0.215molFe\times \dfrac{2molAl}{2molFe}\times 26.982g/mol=5.80g$

6. Aluminum oxide

• molar mass Al₂O₃: 101.96g/mol

• mole ratio: 2mol Fe: 1 mol Al₂O₃

       $0.215molFe\times \dfrac{1molAl_2O_3}{2molFe}\times 101.96g/mol=11.0g$