Sulfuric acid dissolves aluminum metal according to the reaction:

2 Al(s) + 3 H₂SO₄(aq) → Al₂(SO₄)₃(aq) + 3 H₂( g)

Suppose you want to dissolve an aluminum block with a mass of 15.2 g. What minimum mass of H₂SO₄ (in g) do you need? What mass of H₂ gas (in g) does the complete reaction of the aluminum block produce?

Video transcript

Hey everyone, we're told that we want to dissolve an aluminum rod, weighing 1.5 kg. What is the minimum mass of sulfuric acid and grams required to react with aluminum? How much in grams of hydrogen gas is produced if the aluminum rod reacts completely And they provided us with our reaction. Now, before we answer this question, let's first see if our reaction is completely balanced out assessing this a bit further. We do need to balance this out and we can do so by adding a coefficient of two prior to our aluminum, a coefficient of three prior to our sulfuric acid and a coefficient of three prior to our hydrogen gas. Now our reaction is completely balanced out. So to answer this question, we need to use dimensional analysis. We want to take our 1.5 kg of aluminum and convert this into grams of sulfuric acid and also convert it into grams of hydrogen gas. So let's first determine the amount of grams of sulfuric acid. So starting off with 1.5 kg of aluminum, we're going to convert this into grams. Now we know that per one kg we have 10 to the third grams. Using aluminum's moller mass. We know that we have 26.98 g of aluminum per one mole of aluminum. And we can find this in our periodic table. Next, looking at the multiple ratios in our chemical reaction, we see that per two mole of aluminum, We have three mol of sulfuric acid. And this is coming from our coefficients right here. Next, using sulfuric acids molar mass, We know that we have 98.09 g of sulfuric acid Per one mole of sulfuric acid. Now, when we calculate this out and cancel out all of our units, We end up with a total of 8,180. g of sulfuric acid. Next, let's go ahead and convert our 1.5 kg of aluminum into grams of hydrogen gas. So taking the same steps, we're going to convert our kilograms into grams and we know that per one kg we have 10 to the third grams And we know that we have 26.98 g of aluminum per one mole of aluminum. Since this is aluminum's molar mass. Now looking at the multiple ratios between aluminum and hydrogen gas, we can see that we have two mole of aluminum, her three mole of hydrogen gas. And again, this is coming from our coefficients in our chemical reaction. And using hydrogen gasses, molar mass, we know that we have 2.2 g of hydrogen gas per one mole of hydrogen gas. Now, when we calculate this out and cancel out our units, We end up with a total of 168.46 g of hydrogen gas. And these will be our final answers. Now, I hope this made sense. And let us know if you have any questions