Calculating mass of sulfuric acid to affect ph change

Question

Assignment:

Use of H₂SO₄ to adjust the pH of a solution:

Question 1. How many grams per liter of H₂SO₄ is required to adjust the pH of a solution from 3.8 to 2.8 assuming the sulfuric acid fully ionizes?

Question 2. If in reality however, the actual sulfuric acid ionization/dissociation is a 2 step process and not fully ionized such that:

If, K₁ = [H⁺][HSO₄^-]/[H₂SO₄] is complete and is equal to 100 mol/L,

But if the second reaction is not complete such that:

K₂ = [H⁺][HSO₄^-]/[HSO₄^-] is incomplete and equal to .012 mol/L,

then how many grams/liter of sulfuric acid in this case would be required to change the pH of the solution from 3.8 to 2.8?