What volume of 5.0 M H2SO4 should be diluted to 100mL to prepare a 0.25 M H2SO4 M solution?

Question

I know the molar mass of H2SO4 is 98g but I'm not sure where exactly that fits in and how I'm supposed to get it to be diluted.
Thank you!

Answer 1

The general formula for a dilution is

M₁V₁=M₂V₂

Look familiar? Notice how MV is the number of moles. The number of moles of H₂SO₄ solution do not change.

So, all we have to do now is plug in what we know, and solve for the unknown, which is V₁.

(5.0 M)V₁ = (0.25 M)(100 mL)

V₁ = 5.0 mL

Therefore, 5.0 mL of the 5.0 M solution of H₂SO₄ should be diluted to get 100 mL of a 0.25 M solution of H₂SO₄.

Answer 2

another way.
You want to dilute it 5/.25 or 20 times.
That means 19 parts water, one part stock acid. so you need 1/20 *100ml of stock solution. or 5 ml.