You make two liters of a 3.0 pH solution of H2SO4:

You make 2 liters of a 3.0 pH solution of H2SO4:
1. how much water will i need to add to make the pH4.0 / 5.0?
2. How many more times more dilute is a 1.0 pH solution than the original?
3. What is the concentration of [h+] in the 1.0 pH solution and in the 3.0 ph solution?
4. If you have one mole of H2SO4, How many hydrogen ions are there? sulfate ions?

Re: You make two liters of a 3.0 pH solution of H2SO4:

mle219 wrote:
You make 2 liters of a 3.0 pH solution of H2SO4:
1. how much water will i need to add to make the pH4.0 / 5.0?

If they told you it's a strong acid, you really would not need to know which acid it was to answer this part.
A strong acid is completely dissociated into ions in the pH range of 1.0 to 5.0.
Also, in that pH range, the amount of H+ ions contributed by water will be insignificant compared to the amount coming from the acid.
As a consequence, you can assume that all the H+ in solution comes from H2SO4, and that all the H in H2SO4 is in solution as H+ ions, before, and after diluting.
You only need to know the concentrations of H+ ions.

Since pH = -log[H+], [H+] = 10-pH

So, for pH = 3.0, H+] = 10-3.0M = 0.001M

For pH = 4.0 and 5.0, you can calculate [H+] similarly.

Once you know the concentrations before and after, you can easily calculate how much to dilute.

For example, if you needed to dilute to 0.0001M, since the pH = 3.0 solution is 0.001M, you would be diluting 10 times. The final volume would be 20 liters. You would have to add 18 more liters.

Re: You make two liters of a 3.0 pH solution of H2SO4:

mle219 wrote:
You make 2 liters of a 3.0 pH solution of H2SO4:
1. how much water will i need to add to make the pH4.0 / 5.0?
2. How many more times more dilute is a 1.0 pH solution than the original?

What do you mean by the original? Is it the pH=3.0 solution?

And what is a 1.0 pH solution? Did you mean a solution 1.0 higher in pH?

A pH=1.0 solution would be much more concentrated than a pH=3.0 solution.

Within limits, each increase of 1.0 units in pH means a solution ten times more dilute. The "limits" are in that at less than pH=1.0, even a strong acid may not be quite 100% dissociated, and that at pH>5 the H+ and OH- ions contributed by water would matter, and you could never get to pH>7 just by diluting an acid.

mle219 wrote:
3. What is the concentration of [H+] in the 1.0 pH solution and in the 3.0 ph solution?

In a solution with pH=1.0, [H+], the concentration of H+, would be 0.1M,
pH = -log[H+], and
[H+] = 10-pH