How many mL of 0.72 M H2SO4 solution are needed to react completely with 12.29 g of Fe2O3 in the following reaction? Fe2O3(s) + 3H2SO4(aq) → Fe2 (SO4)3(aq) + 3 H2O(l)

Answer 1

For this problem, you will start with the grams of Fe₂O₃, then find moles Fe₂O₃ using the molar mass, then moles of H₂SO₄ using the balanced equation, then mL of H₂SO₄ solution using the molarity of the H₂SO₄ solution. Remember that molarity is really moles per liter, so 0.72 M can be written as 0.72 moles per 1 L or 0.72 moles per 1000 mL:

12.29g x 1 mol Fe₂O₃/159.70g x 3 mol H₂SO₄/1mol Fe₂O₃ x 1000 mL/0.72 mol H₂SO4

To calculate the answer: 12.29 divided by 159.70 times 3 times 1000 divided by 0.72 = 321 mL of the H₂SO₄ solution. Notice that there are only two significant figures in the given molarity (.72) so you need to round your final answer to two significant figures: 320 mL

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