Home > categories > Minerals & Metallurgy > Aluminum Foils > how many moles in 15.00 grams of Aluminum Bromine? Help!!!!!?
Question:

how many moles in 15.00 grams of Aluminum Bromine? Help!!!!!?

How do I find the number of moles? Help, please!!!!!!

Answer:

First, understand what a mole actually isThis is just a number chemists use to express weightThis many atoms of any element equals it's atomic weight in the periodic tableAluminum has an atomic weight of 27 grams/mole and Bromine is 80 grams/moleMolecular weight is the sum of atomic weightsNext, study chemistryIf you do, you will know Aluminum has a valence of 3 and Bromine has a valence of 1What this means is an Aluminum atom can bond to 3 Bromine atoms, making the chemical formula of Aluminum bromide AlBr3The molecular weight of AlBr3 is 27 + 380 267 grams/mole Having gotten this far, it is rather easy to see 15 grams/(267 grams/mole) 0.06 moles AlBr3FYI: working chemists round atomic weights which is perfectly acceptable in the real worldHowever, chemistry class is not the real worldLots of instructors will deduct points if exact atomic weights are not usedFor example, the exact atomic weight of Aluminum is 26.9815 grams/mole.

Share to: