How many grams are formed?

Question

Iron(III) oxide is formed when iron combines with oxygen in the air. How many grams of Fe₂O₃ are formed when 25.9 g of Fe reacts completely with oxygen? 4Fe(s) + 3 O₂(g) → 2Fe₂O₃(s) 

a.12.0 g
b.25.0 g
c.37.0 g
d.49.0 g

 

Answer 1

First thing you would have to do in this problem is figure out the molar weight of iron (Fe) in order to determine how many moles of iron are involved in the reaction.

 

Once you figure out the number of moles of iron in the reaction, you must then determine the molar weight of the iron (III) oxide, which you will also need a table of elements for. The ratio of moles of iron in the reaction and moles of iron (III) oxide is 2:1, since for every 4 moles of iron you get 2 moles of iron (III) oxide. Multiplying the amount of starting moles by the molar ratio, with the denominator denoting the moles of iron and the numerator denoting the moles of iron (III) oxide, to determine the total amount of moles of iron (III) oxide produced.

 

Once you know the number of moles produced, you can then use the molar weight of iron (III) oxide to determine the total weight of the product in grams.

 

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