Calculate [H+] and [OH -] for each solution at 25°C?

Question

pH = 7.40
[H+]=??
[OH -]=??

pH = 15.1
[H+]=??
[OH -]=??

pH = -1.0
[H+]=??
[OH -]=??

pH = 1.61
[H+]=??
[OH -]=??

pOH = 4.0
[H+]=??
[OH -]=??

pOH = 8.52
[H+]=??
[OH -]=??

Answer 1

Boy, you really need to pay attention in the classroom. Please read the textbook as well. Pay special attention to the definitions.

The definition: pH = - log([H+])
Therefore: [H+] = 10^(-pH)
[OH-] = 10^(-14)/ [H+] = 10^(-14+pH)
where 10^x means 10 to the power of x. For example, 10^2 = 100, 10^0 = 1.

Now I have listed all necessary formulas you have to use to solve these very simple practices. You need to do the math.