Ion equation for reaction of magnesium oxide and dilute sulfuric acid?

Ion equation for reaction of magnesium oxide and dilute sulfuric acid?

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When iron powder is added to the mixed solution of dilute sulfuric acid and copper sulfate, with which substance does iron react first? The problem seems a little idiotic... In fact, the reason for this question is because of the following question. Add 10 g of CuO powder to 100 g of dilute sulfuric acid with a certain mass fraction, slightly heat until the copper oxide is completely dissolved, then add mg of iron powder to the blue solution, after full reaction, filter, and dry the filter residue to obtain dry solid substance mg. Find:(1) mass fraction of solute added with dilute sulfuric acid; (2) When m is taken, the added iron powder and the solid mass are equal. Solution: copper in 10g CuO=[64/(64+16)]*10=8g, then m=8 relative mass of copper/relative mass of iron=64/56=8/7, that is to say,7g iron completely displaces copper. The remaining 1g iron is dissolved in dilute sulfuric acid and the solution is FeSO4. Fe contains 8g. According to CuO+H2SO4=H2O+CuSO4 and Fe+CuSO4=Cu+FeSO4 and Fe+H2SO4=H2↑+FeSO4, the sulfate radical in FeSO4 is the original sulfuric acid. The mass of sulfuric acid can be calculated from the mass of (relative mass of sulfuric acid/relative mass of FeSO4) FeSO4,(mass of sulfuric acid/100)*100%= mass fraction of sulfuric acid=14% Standard answer:14%; m≥8 This is almost the standard answer, but I have never understood why "the sulfate in FeSO4 is the original sulfuric acid "? Is it certain here that the sulfuric acid has been removed? What if sulfuric acid is left after all the reactions? Is it iron powder that reacts with sulfuric acid first, then with copper sulfate after the sulfuric acid is consumed (if so, it seems impossible), or with copper sulfate first? In the latter case, if the mass fraction of sulfuric acid is greater than 14% and 8 g of iron powder is added, isn't the replacement copper also 8 g? I saw someone on the Internet say the answer should be 14% or more; m =8, I think it makes sense. Or is the subject itself problematic?

Of course iron reacts with copper sulfate first, without doubt
In fact, there is only one case in which the concentration of sulfuric acid can not be determined, i.e. when m=8, m=8,7g of iron displaces 8g of copper, and the remaining 1g completely reacts with sulfuric acid, but it can not be determined whether the sulfuric acid remains. When m >8, the same 7g of iron displaces 8g of copper, and the residue contains (m-8) g of iron, and 1g of iron reacts with sulfuric acid, and the sulfuric acid must react completely due to the remaining iron. It is very tiring to type on the mobile phone.
Supplement:
The first question must be based on m >8 to determine the sulfuric acid concentration of 14%(I have not calculated); the second question must be based on the sulfuric acid concentration of 14%, that is to say, the Fe reacting with H2SO4 is just 1g, so as to ensure that the amount of iron powder added is equal to the dry solid substance. Do you understand?