[jimbo999]

Im currently in chem 111 and need help with a stoichiometry question. Anyones help would be appreciated.

Hydrobromic acid dissolves solid iron according to the following reaction:

Fe(s) + 2HBr(aq)----> FeBr2(aq) + H2(g)

What mass of HBR (in Grams) would you need to dissolve a 3.2g pure iron bar on a padlock? What mass of H2 would be produced by the complete reaction of the iron bar?

Alright, I'm not just looking for an answer I would appreciate if someone could show how to answer the question using stoichiometry.

I know the given is the 3.2g of Fe and I need to find the mass of HBR needed to dissolve the 3.2G but I dont know where to start from here

Thanks,
            Jim

[Bob Sacamano]

Start by finding how many moles of Fe are contained in the padlock using its molar mass found on the periodic table.

Then you can use the mole ratio between Fe and HBr to find the number of moles of HBr you will need to completely dissolve the Fe.

Then convert the number of moles of HBr to the mass of HBr required using the molar mass of HBr, found by taking the sum of the molar masses of H and Br found on the periodic table.