An aqueous solution at 25 c has a OH- concentration of . Calculate the concentration. Be sure your answer has the correct number of significant digits.

Full Question:

An aqueous solution at 25 C has a OH- concentration of 2.5x10-4M . Calculate the H3O+ concentration. Be sure your answer has the correct number of significant digits.

4×10−9M

Explanation:

From the question;

[OH−] = 2.5x10-4M

[H3O+] = ?

The relationship between both parameters is given as;

Kw = [H3O+] * [OH−]

where k self-ionization constant of water, Kw = 1×10−14, which has no units.

Upon solving for [H3O+];

[H3O+] = Kw / [OH−]

Kw = 1×10−14

[H3O+]  = (1×10−14 ) / 2.5x10-4

[H3O+]  = 0.4 * 10-10

[H3O+]   = 4×10−9M

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !