Question

In the reaction of fe3o4 with carbon to form carbon dioxide and iron, the number of moles of carbon required to convert 23 g of fe3o4 to products is

Answer 1

0.20 moles First, create a balanced equation, which is Fe3O4 + 2C => 2CO2 + 3Fe Now calculate the molar mass of Fe3O4, first lookup the atomic weights of the elements involved. Atomic weight iron = 55.845 Atomic weight oxygen = 15.999 Molar mass = 3 * 55.845 + 4 * 15.999 = 231.531 g/mol Calculate the number of moles of Fe3O4 you have 23 g / 231.531 g/mol = 0.099338749 mol Looking at the balanced equation, you can see for each mole of Fe3O4 you have, you need 2 moles of carbon. So multiply the number of moles of Fe3O4 by 2 0.099338749 mol * 2 = 0.198677499 mol Since you only have 2 significant figures in your data, round the result to 2 figures, giving 0.20 moles

Answer 2

From the periodic table:
mass of oxygen = 16 grams
mass of carbon = 12 grams
mass of iron = 55.84 grams
Therefore:
molar mass of Fe3O4 = 3(55.84) + 4(16) = 231.52 grams
number of moles = mass/molar mass
number of moles of Fe3O4 = 23 / 231.52 = 0.099 moles

The balanced chemical equation that describes this reaction is:
Fe3O4 + 2C --------> 2CO2 + 3Fe
From the balanced reaction above, we can note that:
one mole of Fe3O4 requires two moles of carbon to react with.
Therefore, to know the number of carbon moles required to react with 0.099 moles of Fe3O4, all you have to do is cross multiplication as follows:
number of carbon moles = (2*0.099) / 1 = 0.198 moles