Question

The overall reaction in a commercial heat pack can be represented as 4Fe(s) + 302(g). 2Fe,03(s) -1652 kJ a. How much heat is released when 4.80 moles of iron are reacted with excess O2? Heat kJ b. How much heat is released when 1.00 mole of Fe2Os is produced? Heat = kJ c. How much heat is released when 1.70 g iron is reacted with excess O2? Heat kJ d. How much heat is released when 10.6 g Fe and 1.80 g O2 are reacted? Heat kJ

Answer 1

from given balanced equation
4 mols Fe releases energy = 1652 KJ
a) heat released when 4.8 mol Fe reacted= 1652 KJ/4mol *4.80 mol
= 1982.4 KJ
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b)
from balanced equation,
2 mole Fe2O3 releases heat = 1652 KJ
so

1 Mole Fe2O3 releases heat = 1652 KJ/2 =826 KJ
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1.70 g Fe = [1.70g Fe/55.845 u] mols of Fe
=0.03044 mols

4 mols Fe releases energy = 1652 KJ
a) heat released when 0.03044 mol Fe reacted= 1652 KJ/4mol *0.03044 mol
=12.57 KJ
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d)
10.6 g Fe = [10.6 g/55.845 u] mols of Fe = 0.1898 mols

1.8 g O2 = 1.8 g/32 g/mol=0.05625 mols

Since mols of O2 present is smaller than mols of Fe present, O2 will be the
limiting
reactant. The reaction will stop once all O2 is consumed. There would
be some excess moles of Fe present in the reaction mixture.

According to balanced reaction
3mol O2 releases heat =1652 KJ
thus 0.05625 mols O2 releases heat = 1652 Kj/3 mol* 0.05625 mols
= 30.975 KJ
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