Hydrobromic acid dissolves solid iron according to the reaction:

Fe(s) + 2 HBr(aq) → FeBr₂(aq) + H₂( g)

What mass of HBr (in g) do you need to dissolve a 3.2-g pure iron bar on a padlock?

Video transcript

Hey everyone. Our question here is asking us to determine how many grams of hydrogen bromide are needed to completely dissolve 1.3 kg of pure iron. Looking at our reaction, we can see that it's unbalanced since we have two hydrogen in our product side and only one in our react inside. So we're going to need to balance this out by adding a two before our hydrogen bromine. And this works because now we also have to bro means in our product and in our react inside. Starting off with our 1.3 kg of pure iron, we're going to first convert this into g and so we know that per one kg we have 10 to the 3rd g. And now we want to convert our grams into moles of iron. And so looking at our periodic table, we can see that the Mueller massive iron is going to be 55.85 grams per mole. Now we want to relate this to our hydrogen bromide. Looking at our reaction, we can see that per one mole Of iron, we have two moles of hydrogen bromide and finally, we want to convert our hydrogen bromide instagrams and we're going to do so by calculating our molar mass. And when we do that, we find that hydrogen bromide Mueller mass is going to be 80. g per mole. So when do you calculate this out, we're going to end up with a value of 3766.62 g of hydrogen bromide, Which we can further simplify into 3.8 times 10 to the third grams of hydrogen bromide. And this is going to be our final answer. So I hope this made sense and let us know if you have any questions.