If 201 g Fe2O3 is reacted with excess CO, what mass of CO2 will be produced? Fe2O3(s) + 3CO(g) → 3CO2(g) + 2Fe(s)

Question

I need help ASAP

Answer 1

Hello, Lisa,

You are keeping me busy. Please work on your other problems as far as you can and then ask about the step which is causing the most confusion.

The equation you provided is balanced.

Fe₂O₃ + 3CO(g) → 3CO₂(g) + 2Fe(s)

It tells us to expect 3 moles of CO₂ per 1 mole of iron oxide (rust)

If we have 201 grams of Fe₂O₃, we have (201g/159.7 g/mole) = 1.26 moles of the stuff. Three times that means 3.78 moles of CO₂. Converting to grams by using the molar mass of carbon dioxide, we arrive at 166 grams of the greenhouse gas.

For extra credit, we need 3.78 moles of CO (105.8 grams) and we produce 252 moles of Fe (140.6 grams). The sum of reactant masses is 306.8 grams and the sum of the product masses is, hold on, . . . 306.8 grams, as per the law of conservation of matter.

Bob

Answer 2

In this problem you know that the iron oxide is the limiting reactant. So start your work with the number of grams of this reactant. You will want to use three factors or ratios to connect this amount of reactant, to the amount of product CO₂ that can be made from this reactant. The first factor will use the inverted molar mass of the iron oxide (be sure to use the molar masses of Fe and O along with the subscripts in the formula of this compound to complete this calculation) to convert to mol of iron oxide reacted. Second, use a mol/mol ratio using the balanced reaction equation, putting the mol of CO₂ amount on the top of the ratio. This 2nd factor will get you to the mol of the product made by the iron oxide. Lastly calculate the molar mass of the carbon dioxide product compound and use that as the 3rd factor to find the g of CO₂ that the iron oxide reactant amount can make. When you write out the work be sure to include and cancel out units on your 3 factors. The 'remaining' unit should be g of CO₂ and then just multiply and divide the various values to find the numerical answer. Note that this process will work in relating the gram amount of one reactant to the gram amount of a different reactant needed to 'use up' all the 1st reactant. Or to find the gram amount of a given reactant needed to make a certain gram amount of a given product in the reaction.