How many moles of Fe2O3 are in 205 g of the compound?

Answer 1

Hello, Darragh,

First determine the molar mass of Fe₂O₃. Add the atomic weights of two iron atoms and three oxygen atoms. That should add to around 159.7, which becomes the molar mass when we assign the unit g/moles. If we have 205 g of Fe₂O₃, then divide the mass by the molar mass:

205g/(159.7 g/mole)

Note how the grams cancel and mole moves to the top. Express the answer in 3 sig figs. Without calculating, you should see that the answer should be a little over 1 mole. You have 205 g, and one mole requires 159.7 grams. It's good to predict an answer before calculating, just to check on whether you've entered the correct keystrokes.

Bob